SET 1

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Tab

console.log([4, 6, 7, 12].findIndex(isPrime));

"foo" || "bar";

"foo";

: sort

sort cmmand sorts lines of text file alphabetically or some other order

Subtract one to n using bit ops

~-n

CMD: bash

A command-line interface

What is a vector in linear algebra?

A vector is a list of numbers (can be in a row or column) - think Array. n x 1 matrix (https://en.wikipedia.org/wiki/Row_and_column_vectors)

system.js

A dynamic module loader compatible with the ES2015 module specification. There are other viable choices including the well-regarded webpack. SystemJS happens to be the one we use in the documentation samples. It works.

Don't Criticize, Condemn, or Complain - Thomas Carlyle

A great man shows his greatness by the way he treats little men.

Write a regex to find Jennifer, Jen or Jenny and a last name using a bracket quantifier

/(Je[nnifer|nny|n]{1-6}\s\w+\s/

var foo = function() { ... }

ANONYMOUS FUNCTION EXPRESSION

First frat chapter west of Allegheny Mountains?

Alpha Delta Phi at Miami University - 1833

X-.org-X11

An X server system and is the default X server used by most Linux Distros

String.prototype.concat()

The concat() method combines the text of two or more strings and returns a new string.

Abstraction definition

The conjunction of an object's complex inheritance, methods, and properties must adequately reflect a reality model.

is it a good practice to invoke a function like this? window.myFunction(10, 2);

This is a common way to invoke a JavaScript function, but not a good practice in computer programming. Global variables, methods, or functions can easily create name conflicts and bugs in the global object.

String.prototype.startsWith()

The startsWith() method determines whether a string begins with the characters of another string, returning true or false as appropriate. str.startsWith(searchString[, position])

Character-oriented device files

These files are used for devices that receive data sequentially one character at a time; such as a printer, mouse, or tape-drive. Thse deviceses usually dont support random access to the data stored on them.

Polynomial functions

These functions consist of one or more terms of variables with whole number exponents. (Whole numbers are positive integers and zero.) All such functions in one variable (usually x) can be written in this type of format: constant, linear, quadratic, cubic, quartic, quintic

∈

is in, element of..

: which

used to display full path to a shell command or utility

: exit

used to exit a running process

∀ meaning?

for all..

NPC

national panhellenic conference organized in 1902 and now includes 26 women's fraternities

: ping

ping utility checks if network interface is working correctly thhe destination system is up and working correctly network hardware between your system and the destination system is wokring correctly -- uses ICMP echo request packet

What is a synonym for lexical scope?

Static scope

What is ES.next?

The next version of Ecmascript

undo

CMD: init 0

switches system to runlevel 0, which halts the system

Manual renamed what

The Olympian of Phi Delta Theta

FLOSS - Free Libre Open Source Software

...

CMD: gcc

A C++ compiler

Inheritance definition

A class can inherit characteristics and capabilities from another class.

How to sort an array from lowest number val to highest?

Array.prototype.sort( (a,b) => a - b));

Node.appendChild()

Node.appendChild() method adds a node to the end of the list of children of a specified parent node. If the given child is a reference to an existing node in the document, appendChild() moves it from its current position to the new position.

Block-oriented de ice files.

These files are used fordevices that manage data in blocks; such as floppy disks and hard drives. Block devices usually support random access ot the data stored on them

What are free variables?

Variables that are used locally, but defined in an enclosing scope.

Brethren is

archaic

$PS1

characters used to create shell prompt

example of call()

function myFunction(a, b) { return a * b; } myFunction.call(myObject, 10, 2); // Will return 20

What are the regular expression flags?

g i m y

What is the value of "this" when used in a function?

it is the object that "owns" the function.

move file or directory

move left

Does String.prototype.split() mutate the String given?

open blank line above current line

www.sourceforge.net

place to find OS software

popd

pop directory

: cpio

provide cpio wih LIST of files and directories from standard input. ls | cpio -ov > /media/usb/backup.cpio

pushd

push directory

What is the question mark called?

quantifier

man

read a manual page

replace a single character (does not use insert mode)

:%s/old/new/g

replace all old with new throughout file

Session

responsible for establishing connections between source and destination network hosts. these connections are called sessions.

How to take a string s and break it into an array of string characters?

s.split('');

VI : ZZ

saves current file and ends vi

CMD: halt

shuts down the system

union triad

sigma phi, delta phi, kappa alpha society.

ssh

ssh client used to connect to the sshd daemon on another system

Ctrl + v

start visual block mode

Linux Backup Utilities

tar, cpio, dd

Palmer's objectives are defined in

the bond of phi delta theta which every member admitted to the fraternity pledges himself to uphold. bond will remain involate and unalterable

unicast

the route specifies a real path to the destination route

console.log([4, 6, 8, 12].find(isPrime));

undefined

VI : u

undo

*~ files

usually temporary files end with the tilde

Create a class called Person

var Person = function () {};

How to check if a value is NaN?

x !== x or isNan()

if (x == 3) { x += 2; return x} else {return 0}; with ternary operator minimizing parens

x == 3 ? ( x +=2, return x) : return 0

Find the partial derivative of 3x-2y^4 with respect to x and with respect to y.

you treat everything else as a constant f_x = 3 f_y = -8y^3

Sam Vexler

1380

Daniel Sullivan

1381

Jay Stemmer

1383

Nick Luthi

1388

Alex Mobashery

1389, Secretary, Co-Brotherhood Chair

Chris Turner

1390

Conor McDonough

1395

Sebastian Perez

1396

Hunter McComas

1397

Dakota Ford

1398

Joe Geyer

1399, Community Service Chair

Gustavo Velazquez

1400

Emerson Delgado

1402, Ex-Comm Member at Large

Bryan Popoola

1404, Phikeia Educator

Nick Gallagher

1407

Mihir Dubey

1408

Ryan Keem

1409

Get absolute value of n using bit ops?

(n ^ (n >> 31)) - (n >> 31);

find

find files

Apache

most popular web server

/dev/scd0

optical drive

IEEE 1394a

400Mbps

802.11a

5Ghz 54mbps

What is Node's execution model?

Asynchronous, single-threaded, event-driven execution model.

Miami Triad

Beta Theta Pi, Phi Delta Theta, Sigma Chi

What are the three sources of Node modules?

Built in modules, your own project files, third party modules

Latency is measured in what?

CL, CAS

How to change a linear regression to better fit a data using the same features?

Change the order of the polynomial model by taking the order of the polynomial model and just applying it to the features you do have.

Divisible by 4?

Check last two digits, if divisible by 4 then it is divisible by 4. Also note that all divisble by 4 numbers end in 0,4,8,2,6

First General Convention

Cincinnati 1851

/etc/X11

Contains X Window config files

grep

find things inside files

49152 - 65535

Dynamic and Private

:e filename

Edit a file in a new buffer

Shift + CMD + A

Find Action

First man pledged to PDT

Morton George Williams

port 25

SMTP

Double Shift

Search everywhere

@angular/upgrade

Set of utilities for upgrading Angular 1 application2

Union Triad

Sigma Phi 1827, Delta Phi 1827, Kappa Alpha Society 1825 -- Union College in NY

Synonym for output variable?

Targets

What does the R mean in matrices?

The set of all rows x columns matrices

0-1023

Well Known Ports

Writer

Word Linux

alpha delta pi

founded as first sisterhood

select()

highlights text in the textarea object

: grep -i

ignore case grep

less

page thru a file

Presentation

responsible for ensuring that infomration passinh through the OSI layers is formatted correctly for the application on the destination system

∴

therefore

rpm vs yum

yum gets depndenceies

:xargs

use xargs to break down a long command line into 128 KB chunks and pass each chunk as an argument to the command listed within the xargs command line.

GNOME Terminal

run terminal in runlevel 3 -- for GNOME

Remember names and use them - Jim Farley

" I can call fifty thousand people by their first name"

Smile - Chinese proverb

"A man without a smiling face must not open a shop"

ES6: let name = 'Bob'; String.raw`Hi\n${name}!`; returns?

"Hi\nBob!"

how do you write a for loop that iterates through an array backwars

for (var i = 0; i < arr.length; i++){ console.log(arr[arr.length-1-i]); } for (var i = testArr.length-1; i >= 0; i--){ //console.log(testArr[i]); } var goToLoop = function(){ for (var i = testArr.length; i --> 0;){ console.log(testArr[i]); } return "DONE"; }

Self contained modules

everything with my module is in my module no global variables if a module manages more than one thing it should be broken up

xargs

execute arguments

esc

exit insert mode

exit

exit the shell

esc

exit visual mode

VI Commands

exit, wq, q, w!, e! (forgets changes since last write)

** ES6

exponentiation

exporting user variables

export (VAR NAME)

export

export/set a new environment variable

:export PATH

exporting variables to be available in other shells.

Linux Filesystems

ext2, ext3, Reiser, ext4

What are the Javascript falsy values?

false, 0, "", null, undefined, NaN

: locate

find is slow and lcoate is a alternative. its more efficient

freshmeat.net

find packages

linux.tucows.com

find packages

apropos

find what man page is appropriate

: umask

find what ur umask is

Finding files in Linux FS

find, locate, which whereis, type

Beta Theta Pi is the first what...

first fraternity founded west of the Alleghenies

: cat myfiles.odt 2> errorfile

if myfiles doesnt exist puts error code intoo errorfile.

ifconfig syntax

ifconfig interface ip_address netmask subnet_mask broadcast broadcast_address -- e.g. assign eth0 interface to 192.168.1.1 subnet mask of 255.255.255.0 and a broadcast address of 192.168.1.255 "ifconfig eth0 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255"

AES

improved version of 3DES

How many ways can js functions be evoked?

in 4 different ways.

robert morrison was exceptional scholar

in Greek and Latin

inner () block

inner {} block

insert at the beginning of the line

VI : p

insert text in last deletion operation after cursor location

How to inspect the third a tag when JQuery is used while using $?

inspect($("a")[2]); (https://api.jquery.com/category/selectors/)

How to inspect document.body when JQuery is used while using $?

inspect($(document.body)[0]); (https://api.jquery.com/category/selectors/)

Sound learning

intellectual curiosity and a search for truth.

Southbridge

intermediary between PCI bus and other expansio buses on the motherboard.

what's important about ES6 in regards to recursion?

introduces "proper" tail calls!

123.toString();

invalid token

high scholastic achievement

is almost impossible without a sense of intellectual curiosity and a drive for truth and understanding.

: killall (more convenient at times)

killall uses command name of process to kill isntead of PID .. use killall -15 vi to kill vi.

RAID 10

mirrored sets in a striped set

RAID 1

mirroring

ModEvasive

mod_evasive is an evasive maneuvers module for Apache to provide evasive action in the event of an HTTP DoS or DDoS attack or brute force attack. It is also designed to be a detection and network management tool, and can be easily configured to talk to ipchains, firewalls, routers, and etcetera. mod_evasive presently reports abuses via email and syslog facilities.

what pattern does this exhibit? var Toaster = function(){ //private here var status = false; var voltage = 3.0; var manufacturer = 91745321; var changeVoltage = function(num){ voltage = num; }; return { toggle : function() { status = !status; }, showStats : function(){ console.log(voltage); console.log(status); console.log(manufacturer); }, toast : function(bread){ bread === 'new' ? bread === 'toasty' : bread === 'burnt'; }, callManufacturer : function(){ console.log(manufacturer); } }; };

module pattern -- how does it work? how are the private variables private? how are certain methods privileged and some are public?

rectitude

moral integrity & correctness of judgment

Convention of 1880 importance

most important, general council and provinces were adopted. State Grand Chapter and National Grand Chapter were abolished, the executive committee was discontinued and the supremer power of the Fraternity was vested in the General Convention.

/dev/log/

most linux services are configured to write log entries to /dev/log by default -- this device file is maintained by the syslogd daemon the syslogd daemon writes entries into the /etc/syslog.conf file

move to other end of marked area

: fg

moves a background process to foreground "fg job_ID"

: bg

moves a foreground process to background -- "bg job_ID"

Classic Module Pattern characteristics

must be an IIFE or an outer function that gets executed. second characteristic, one or more functions that get returned from the function call that have a closure over the inner private scope.

hostname

my computer's network name

myAnimal.speak()

myAnimal['speak']()

until loop

until condition do script commands done

add ";" to end of 3 different lines

use CTRL+v, navigate down three lines, A, write ;, then exit.

add "hello-" to front of 3 different lines

use CTRL+v, navigate down three lines, I, write "hello-" then exit

Brian Yan

1385

Aaron Cendan

1415, Recruitment Chair, J-Board

Drew Willimitis

1428

SDRAM pins

168

WSXGA+

1680 X 1050

RDRAM pins

184

Class C

192-223

Sommy Irani

1373

Cat6

100Mbps, 1000Mbps = Gigabit

/dev/fd0

Floppy drive

default umask

022

Class A

1 - 126, subnet 255.0.0.0.

First black greek letter men's fraternity

Alpha Phi Alpha, Cornell University 1906

Sometimes the reload button doesnt show various options. Why is that?

Developer tools not open

What are the three ways to disable/refresh cache in DevTools?

Hard Refresh, incognito mode, Disable Cache option

SIGHUP (1)

Kill signal 1 -- restarts process after restart process will have same PID. very useful for restarts and changes in config files

why did they name this subject calculus?

It's from the Latin meaning reckon or account (like calculate), which came from using pebbles (calx) to count with.

AJS: What type of scoping rule(s) does JS have? What are the exceptions?

Lexical, exceptions being <eval> and <with>

Define javascript

Lig

Line Break

Set breakpoints

Line number on left

Chromium

Linux version of Google Chrome web browser

console.warn(object [, object, ...])

Prints a message like console.log(), but also displays a yellow warning icon next to the logged message.

PID vs PPID

Proces ID Number -- Parent Process ID Number

LibreOffice

Productivity Suite (derivative of Apache OpenOffice

Prototype-based programming

Prototype-based programming is an OOP model that doesn't use classes, but rather it first accomplishes the behavior of any class and then reuses it (equivalent to inheritance in class-based languages) by decorating (or expanding upon) existing prototype objects. (Also called classless, prototype-oriented, or instance-based programming.)

Linux files

Refgular files, Links, FIFOs, Sockets

Application

Respomnsible for providing applications with a way to access the network.

Who stole our pin?

Sigma Tau Gamma

Object.getPrototypeOf()

The Object.getPrototypeOf() method returns the prototype (i.e. the value of the internal [[Prototype]] property) of the specified object.

Router vs Request Handlers?

The Router routes the URL the requests are coming in for and routes these requests to the Request Handlers.

In browsers, what are global variables attached to?

The Window!

What does a variable with prefixed underscore mean?

The variable is intended to be private.

/tmp

This directory contains temporary files created by you or the system.

Request Handlers

To fulfill the requests that arrived at the server and have been routed using the router, we need actual request handlers

AJS: What is the official transpiler for TC39?

Traceur maintained by Google. But it only features ES.next features and not future feature sets like Babel does.

What was the significant advance of ML?

Type inference - compiler would infer types based on code.

AJS: IIFE mainstream use?

Used to hide things in anonymous functions within a function expression. The compiler will treat it as a function expression. Recommended to name IIFE for stack tracing purposes. Because the point of the parens or coercing operators is to disambiguate between function expressions and function declarations, they can be omitted when the parser already expects an expression (but please see the

Import a module foo in the current directory

const foo = require('./foo');

/bin

contains executable files and scripts that user may need to run. directory is auto added to $PATH

faillog

contains failed authentication attempts

/Desktop

contains files and icons displayed on desktop

/Downloads

contains files downloaded from the Internet by ksanders' web browser

/etc/passwd

contains your system user accounts

Blu-Ray is connected with?

SATA

SCSI

SCSI implementations can be chained, using ribbon cable and controller. uses jumpers and octal notation 1 2 4 to getSCSI ID's.

RAM TYPES?

SDRAM, DDR, DDR2, DDR3, RDRAM, SODIMM

System Memory (RAM)

SDRAM, DDR-SDRAM, DDR2-SDRAM, DDR3-SDRAM

*S*OLID

SRP - Single Responsibility Principle (https://www.youtube.com/watch?v=Ib-gxqF6Wuk)

Haskell: What operator has highest priority?

function application

Webster's dictionary of rectitude

idea of moral integrity and correctness of judgment

tsch

improved version of csh, default on FreeBSD systems.

Get Max Int (Bit Ops)

int maxInt = ~(1 << 31); int maxInt = (1 << 31) - 1; int maxInt = (1 << -1) - 1;

Get Min Int (Bit Ops)

int minInt = 1 << 31; int minInt = 1 << -1;

How to detect if two integers have opposite signs?

int x, y; // input values to compare signs bool f = ((x ^ y) < 0); // true iff x and y have opposite signs

sound learning ==

intellectual curiosity and a search for truth

the bond will reain...

inviolate and unalterable

If the host resides on a ublic network, such as the Internet,

it must use a GLOBALLY unique IP address

What does J(Theta) increasing tell you about ur gradient descent?

it's not working lol. use a bigger alpha. on the other end if you use too big of an alpha you'll end up with a bowl shaped curve and you might be moving farther away from convergence.

jQuery

javascript library

join line below to the current one

move up

VI : 0 move cursor to start of current line

moves

/dev/ttyS0

serial port

start Linewise visual mode

start insert mode at cursor

$OSTYPE

type of OS being run

: ps

view the processes associated with the CURREN shell.

yank (copy) a line

if/then structures

"if condition then commands else commands fi"

jQuery( selector [, context ] ) is equivalent to

$(); not to be confused with Chrome's default

Write a regex to find Jennifer, Jen, or Jenny and a last name using only one quantifier

(Jennifer|Jen|Jenny)(\b\w+)\b

How are anchors different in what characters they specify?

(The caret, ^ does the r.e. after and $ does the r.e. before. i.e. /^abc$/ -> checks a begin and c end)

Crockford, Closure, Bugs

// This example is explained in detail below (just after this code box). function celebrityIDCreator (theCelebrities) { var i; var uniqueID = 100; for (i = 0; i < theCelebrities.length; i++) { theCelebrities[i]["id"] = function () { return uniqueID + i; } } return theCelebrities; } var actionCelebs = [{name:"Stallone", id:0}, {name:"Cruise", id:0}, {name:"Willis", id:0}]; var createIdForActionCelebs = celebrityIDCreator (actionCelebs); var stalloneID = createIdForActionCelebs [0]; console.log(stalloneID.id()); // 103

write a regex to find calendar or calender when misspelt

/calend[ae]r/

Write a regex to looks for phone numbers with or w/o dashes, with or w/o parens

/t|($?[0-9]{3}$[0-9]{3}\)?[0-9]{4})/

root userid

stdin

0 -- input provided to a particular command to a process

C Major

0 Flats

C Major

0 Sharps

1 % 2

5 % 4

stdout

1 -- output generated from a command

D Minor

1 Flat - Bb

F Major

1 Flat - Bb

G Major

1 Sharp - F#

CLASS A

10.0.0.0 - 10.255.255.255

Class A Private

10.x.x.x

300 % 200

100

Jeremy Pushkin

1371

Austin Little

1372

Class C Private

192.168.xxx

Ab Minor

7 Flats - Bb Eb Ab Db Gb Cb Fb

Web Event: Load

All content loaded (The load event is fired when a resource and its dependent resources have finished loading. https://developer.mozilla.org/en-US/docs/Web/Events/load)

Full Backups

All sepcified files are backed up, regardless of whether or not they've been modified since the last backup. After being baceked up each file is flagged as having been backed up.

Who founded Lambda Calculus?

Alonzo Church (1930)

What function should you use when intentionally iterating with a predicate that produces side effects?

Array.prototype.foreach(predicate) -- as recommended by Kyle Simpson

runlevel5

Boot into a graphical environment -- default config for most desktop linux distros

Where do we put the object when using apply() or call() methods?

Both methods takes an owner object as the first argument.

Save in memory after modifying Sources to see the effect?

CMD + S

AJS: What is the definition of Closure (Kyle Simpson's)?

Closure is when a function remembers its lexical scope even when the function is executed outside of that lexical scope.

When in other tabs how to open console quickly?

Esc or button on right hand side.

Palladians

Every five years after becoming a Golden Legionnaire members receive a pin niscribed

Morton george Williams

FFirst chosen, First Taken, Best Beloved

Smile - Final sentence

For nobody needs a smile so much as those who have none left to give.

GNU

GNU's Not UNIX -- of Richard Stallman

JS Precedence: Grouping vs Logical NOT? () vs !

Grouping ( ... ) (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence)

Is Haskell lazy or strict?

Haskell is often described as a lazy language. However, the language specification simply states that Haskell is non-strict, which is not quite the same thing as lazy.

What is "hypothesis" in machine learning?

Hypothesis: A hypothesis is a certain function that we believe (or hope) is similar to the true function, the target function that we want to model. In context of email spam classification, it would be the rule we came up with that allows us to separate spam from non-spam emails.

AJS: How to avoid pollution of namespace while hiding some variables?

IIFE

How to implement inheritance in Javascript?

Inheritance is a way to create a class as a specialized version of one or more classes (JavaScript only supports single inheritance). The specialized class is commonly called the child, and the other class is commonly called the parent. In JavaScript you do this by assigning an instance of the parent class to the child class, and then specializing it. In modern browsers you can also use Object.create to implement inheritance.

Differential calculus intuition

It answers the question how fast things are changing (instantaneous) at a certain point in time rather than across a long period of time. This is where we attempt to find the slope at a point by using a tangent line. Because we cannot find the slope at a particular point to be precise, we do this by approaching a difference of zero when finding rise over run.

Diamond Legionnaires

Phis for 75 years and more.

The sum of an arithmetic sequence?

S_n = (n(a_1 + a_n))/2

Object.prototype.constructor

Specifies the function that creates an object's prototype.

aLPHA CHAPTER IN EACH STATE

State Grand Chapter

port 23

Telnet

HTTP Server

The HTTP Server "serves" content located in the server, this includes HTML, images, flash and any file related. The server is not restricted to server static content, it also serves dynamic content generated on fly from a database or similar. We want to serve web pages, therefore we need an HTTP server

Pros and cons of using closures for private properties?

The advantage of this technique is that it offers more protection: there is no way for the user to access a private property except by using its getter or setter function. However, the use of closures makes private properties too restrictive: since there is no way to access variables in one closure from within another closure, there is no way for objects of the same class to access each other's private properties.

String.prototype.anchor()

The anchor() method creates an <a> HTML anchor element that is used as a hypertext target.

: cat

The cat filename command will display contents of the specified text file onscreen.

eth0, eth1, eth2

The first Ethernet adapter in your system and so on.

: less

The less filename command can also be used to dispaly text file, but automaticlaly pauses a long text file one page at a time.

String.prototype.link()

The link() method creates a string representing the code for an <a> HTML element to be used as a hypertext link to another URL. str.link(url)

Dependencies vs devdependencies in package.json?

The packages listed under dependencies are essential to running the application. The devDependencies are only necessary to develop the application. They can be excluded from production installations as in this example: $npm install my-application --production

String.prototype.split()

The split() method splits a String object into an array of strings by separating the string into substrings. str.split([separator[, limit]])

String.fromCodePoint()

The static String.fromCodePoint() method returns a string created by using the specified sequence of code points.

Tail Position

The tail position is a postion which an expression would return a value from. There are no more forms evaluated after the form in the tail position is evaluated.

3D Surface Plot - how can it be used to plot the cost function?

Theta 0 and Theta 1 in a univariate linear regression can be plotted on the x and y axes. the Z axis will indicate the actual cost

Training sample definition?

Training sample: A training sample is a data point x in an available training set that we use for tackling a predictive modeling task. For example, if we are interested in classifying emails, one email in our dataset would be one training sample. Sometimes, people also use the synonymous terms training instance or training example.

AJS: What feature had block scope back in ES3?

Try and Catch Blocks. Specifically, just the catch blocks. Unfortunately, JSLint and JSHint and many other linters don't pick up on this and may throw errors.

VGA / DVI

Video adapters

View previous selection in Chrome Inspect

Surround a word with quotes

Visual mode select the word, S, "

What does module.exports do?

You assign variables that are to be exposed to other files as a module to it. one.js: var doIt = function(i, callback){///} var count = 2; module.exports.doIt = doIt; module.exports.foo = 'bar'; two.js: var one = require('./one'); one.doit(23, function (err, result){ // } console.log(one.foo); *Notice the multiple assignments to module.exports* *Notice how you import the FILE as a module due to the 1 to 1 correspondenceness of Node though you can import just single properties *

Exponential decay formula where a = initial amt, r = growth/decay rate, x = number of time intervals

a * (1-r)^x

The else of : if (a >= b) { //execute }

a < b

User processes

associated with soem kind of end-user program running on system -- created from GUI or command line

First charter in a state can only be granted...

by the National Grand Chapter

change (replace) an entire line

Northbridge

controls and manages PCI expansion bus.

AMD define function?

define(moduleId, dependencies, definitionFunc); define(dependencies, definitionFunc); -- preferred anonymous modules typically defaults module to filename // MyApp/MyModule: define( ['pkgA/modA', 'pkgA/modB', 'pkgZ/modC'], function (modA, modB, modC) { var myModule = { doStuff: function() { ... } } return myModule; } );

delete (cut) a line

Erase until and including character

df charactef

head

document metadata used by browsers and search engines

$$(selector) alternative

document.querySelectorAll() ( returns an array of elements that match the given CSS selector)

Erase until and excluding character

dt character

ATTRIBUTE_NODE example?

e.g. class="funEdges"

$SHELL

env variable to find shell type

$PATH

env variables for command bins

PICO: CTRL-X

extis editor when done editing the file.

Quadratic function form?

f(x) = ax2 + bx + c

[1,2,3,4,5].every( a => a > 4);

false

/var/log/lastlog

file contains a list of all users in the system and when they last logged in

: find

find (path) - name "filename" also supports regexps and -user flag and -size or +size flag for more or less

Create a linked list Node Constructor

function Node(data) { this.data = data; this.next = null; }

: grep

grep search_exxp file_name

who enters dining room first

guests and ladies

guy potter benton

guy potter benton, ohio wesleyan 1886, president of miami university.

Haskell: double colon <::> means

has the type <type>

Kyle Simpson's public API classic Module way?

have a variable called publicAPI that is returned as an object. it holds a reference this way and is clear on what is happening. this way you can modify at runtime. whereas if you had an anonymous return value you cannot do so.

How to check if the nth bit is set?

if (x & (1 << n)) { //set } else { //not-set }

/etc/services

maps port numbers to named services on the system

: md

md alias to mkdir

: usermod

modify an existing user account .

Export a module that sums up the area of a square

module.exports = (width) => { return { area: () => width * width }; }

move right

m flag

multiline search

"Moon".match(/\bm/)

null

put (paste) before cursor

put (paste) the clipboard after cursor

Definition of stochastic?

randomly determined; having a random probability distribution or pattern that may be analyzed statistically but may not be predicted precisely.

: renice

renice is used to restart a process with higher or lower nice values -- uses renice nice_value PID

What are the ways to do character access in JS?

return 'cat'.charAt(1); // returns "a" return 'cat'[1]; // returns "a"

download methods

rpm -i, yum , dpkg -i .. yum is different because it downloads dependencies

: apropos

same as the ma -k command use this utility to search across man page names and descriptions to search for names and descriptions of text string

PICO: CTRL-O

saves file currently open

: man -k

search across all man pages for a specific keyword

?pattern

search backward for pattern

0(zero)

start of line

start visual mode, mark lines, then do command (such as y-yank)

⊇

superset of or equal to

TEXT_NODE example?

text characters in an html document including carriage returns and white space

Why would you want to use setTimeout(function cb() { console.log('there'); }, 0); ???

the event loop only pushes tasks onto the stack when the stack is empty. thus, this code waits for the stack to be code. essentially, this defers the execution of the callback until the stack is cleared.

#!/bin/bash

the first line of any shell script must specify which shell the script is writtent o run under. In this case, the /bin/bash shell is specified. When a script is urn, a subhell will becreated using the shell specified here and the script contents will be processed within it.

What are the three ways a function can refer to itself? (Recursion)

the function's name arguments.callee an in-scope variable that refers to the function

X server

the heart of linux GUI, the x server software is the component that draws windows graphically on the display screen. not really a server.

/usr

this directory contains application files In fact most of the application files used on your sysrem are stored in a subd of /usr

/sbin

this directory contains important system managemant andadministration files such as fdisk, fsck, ifconfig, init, mkfs, shutdown, and halt.

etc/group

this file contains your system's groups

SIGTERM (15)

this signal tellsprocess to terminate immediately -- allows the process to clean up after itself before exiting -- default signal sent by kill if you omit a signal in the cmd line

william morgan

traitor of phi beta kappa revealing secrets

[1,2,3,4,5].forEach( a => a + 2);

undefined

What will always(3) return? Given this: function always (n) { return function (n){ return n; } }

undefined (When two arguments or variables in the scopes of a closure have the same name, there is a name conflict. More inner scopes take precedence, so the inner-most scope takes the highest precedence, while the outer-most scope takes the lowest. This is the scope chain. )

PICO : CTRL-U

undoes action

: uniq

uniq command reports or omits repeated lines -d Only print duplicate lines -u only print unique lines

Greeek and Roman Writers saw freindship as..

unity of skills, tastes and thoughts

greek and roman writers saw friendship as...

unity of skills, tastes and thoughts

What does this hypothesis represent? h_theta(x) = theta_0 + theta_1 x

univariate linear regression model

PCIe

updated version of PCI bus that can transfer a lot of data very very quickly. Most modern motherboards include both PCI and PCIe, main thing is that PCI and PCIe dont have to contentd with each other for bandwidth.

~/.bash_profile

user-specific shell preferences

how to get rid of all the falsey values in an array? false, null, undefined, 0, NaN or ""

var a=[1,2,"b",0,{},"",NaN,3,undefined,null,5]; var b=a.filter(Boolean); // [1,2,"b",{},3,5]

: pwck

verify /etc/passwd/ and /etc/shadow/ -- verifies that the two passwors are the same, sometimes they dont stay in sync.

texteditors that i should know

vi, vim, pico, nano

Move forward one word

ls variations

-a, -l, -R

: sort

-f change lowercase characters to uppercase characters -M sort by month, -n sort numerically, -r reverse the sort order

Camron Bagheri

1405

Ziyad El-Mouniri

1406

David Tong

1413, Assistant to Treasurer

Cameron Brown

1418

Roland Li

1420

Brendan Brown

1422, Social Chair, Chorister, Steward

Rohit Satishchandra

1423

Jeff Zhao

1424

Sander Danly

1431

Matt Jeong

1433

CLASS B

172.16.0.0. - 172.31.255.255

GHQ location

Oxford Ohio.

The sum of powers of two is...

2^(n+1) - 1

cat5

100Mbps

Cat5e

100Mbps, 1000Mbps = Gigabit

cat3

10Mbps

What are the two types of Exports?

Named exports: export { myFunction }; // exports a function declared earlier export const foo = Math.sqrt(2); // exports a constant Default exports *(only one per script):* export default function() {} // or 'export default class {}' // there is no semi-colon here

S*O*LID

OCP - Open Closed Principle (Open for extension, closed for modification)

Manual renamed in?

Olympian of Phi Delta Theta

Phi Beta Kappa means?

Philosophy is the guide to life.

Why is this wrong: let arr = [a];

a is not defined (the code will attempt to put the variable a into an object as the value to key 0 i.e. {0 : a})

doctype

declaration of standards compliance

pi beta phi

first organization of ocollege women - 1867

GID

groupid

jump to end of words (punctuation considered words)

move to Other corner of block

1922 Changes to the General Council

offices of secretary and historian were abolished, and two members of the General Council were termed members-at-large. other three members became executivecommittee of the general council.

What does Document.createElement() return?

the element that is created.

: wc

the wc command prints nuber of newlines words and bytes in a file wc -options file

[1,2,3,4,5].every(a => a > 0);

true

RequireJS

Used mainly in the browser. Packages everything into file and helps you manage how JS is loading.

$CPU

type of CPU installed

Array.prototype.length

ACCESSOR method Reflects the number of elements in an array.

Array.prototype.concat()

ACCESSOR method Returns a new array comprised of this array joined with other array(s) and/or value(s).

variable syntax

ALL CAPS

QUEUES ACRONYM

FIFO - enqueue or push, dequeue or pop, size

Port 20 and 21

FTP

: whatis

basically same as man -k and apropos commands, utility searches across man page names and descriptions to search for a text string for example.. z

Port 137, 138, 139

NetBIOS

winter of 1847?

The Great Snowball Rebellioon

[...]

optional

∂ meaning?

partial, often used for partial differentials

Don't Criticize, Condemn or Complain - Lincoln

with malice toward none, with charity for all

Let has what scope?

Block scope

JQuery $(selector [, context ] )

Accepts a string containing a CSS selector which is then used to match a set of elements.

Smile - Self Influencing

Act as if you were already happy, and that will tend to make you happy.

Power Supply

AC -> DC

Array.prototype.toString()

ACCESSOR method Returns a string representing the array and its elements. Overrides the Object.prototype.toString() method.

Do This and You'll Be Welcome Anywhere

Become genuinely interested in people

Array.isArray()

Bool if argument is array

Founders?

John Wolfe Lindley, Robert Morrison Miami 1849

Intel Core 2 use what socket?

LGA 775

Derivatives?

a derivative is the rate of change of a function with respect to changes in its variable

Walter B Palmer

Emory-Vanderbilt 1877

The golden rule of <this>

First, know that all functions in JavaScript have properties, just as objects have properties. And when a function executes, it gets the this property—a variable with the value of the object that invokes the function where this is used.

XFree86

Similar to X.org

: paste

similar to join, paste to files together based on criteria

Create a Student class that inherits from a Person Class

// Define the Person constructor var Person = function(firstName) { this.firstName = firstName; }; // Add a couple of methods to Person.prototype Person.prototype.walk = function(){ console.log("I am walking!"); }; Person.prototype.sayHello = function(){ console.log("Hello, I'm " + this.firstName); }; // Define the Student constructor function Student(firstName, subject) { // Call the parent constructor, making sure (using Function#call) // that "this" is set correctly during the call Person.call(this, firstName); // Initialize our Student-specific properties this.subject = subject; } // Create a Student.prototype object that inherits from Person.prototype. // Note: A common error here is to use "new Person()" to create the // Student.prototype. That's incorrect for several reasons, not least // that we don't have anything to give Person for the "firstName" // argument. The correct place to call Person is above, where we call // it from Student. Student.prototype = Object.create(Person.prototype); // See note below // Set the "constructor" property to refer to Student Student.prototype.constructor = Student; // Replace the "sayHello" method Student.prototype.sayHello = function(){ console.log("Hello, I'm " + this.firstName + ". I'm studying " + this.subject + "."); }; // Add a "sayGoodBye" method Student.prototype.sayGoodBye = function(){ console.log("Goodbye!"); }; // Example usage: var student1 = new Student("Janet", "Applied Physics"); student1.sayHello(); // "Hello, I'm Janet. I'm studying Applied Physics." student1.walk(); // "I am walking!" student1.sayGoodBye(); // "Goodbye!" // Check that instanceof works correctly console.log(student1 instanceof Person); // true console.log(student1 instanceof Student); // true

Important note about <this> value being dynamic.

// let's assume .elem is <div class="elem"></div> var element = document.querySelector('.elem'); // our function var someMethod = function () { console.log(this); }; // when clicked, `this` will become the element element.addEventListener('click', someMethod, false); // <div> // if we just invoke the function, `this` becomes the window object someMethod(); // [object Window]

var x = null || 0; what is x?

(function sayHello() { alert("hello!"); })(); Is this a function expression or a function declaration?

IIFE stands for Immediately Invoked Function Expression. Functions defined via Functions Expressions can be named or anonymous. Function Expressions must not start with "function" (hence the parentheses around the self invoking example below)

when can we say that the function is invoked with a constructor?

If a function invocation is preceded with the new keyword, it is a constructor invocation.

list directory

: man ls /long (long syntax)

long cmd will get a long listing format, load the man page.

env

look at your environment

What are the different ways to duplicate an array in JS?

loop constructor slice / splice concat

lowercase letter convention in reference to matrices?

lowercase indicates vectors, uppercase indicates matrices

false || "bar";

"bar"; (did you note that this is essentially an if-else statement?)

100 % 50

PDT was founded as..

first fraternity aside Phi Beta kappa to be founded on a campus without a Greek letter organization

alpha kappa alpha

first greek frat for black women founded at howard uni

kappa alpha theta

first greek letter society for women - 1870

first non-blank character of line

: fmt

fmt reformat a text file -- use -w to specify characters per row, etc.

different DNS records

CNAME, FQD

Steps of printing

Cleaning, conditioning(charging), writing(exposing) developing, transferring, fusing

.call() vs .apply()

While the syntax of this function is almost identical to that of apply(), the fundamental difference is that call() accepts an argument list, while apply() accepts a single array of arguments.

let arr = [3,2,1]; let dup = arr; arr.sort() whats the value of dup?

[1,2,3]

[1,2,3,4,5].fill(4,1);

[1,4,4,4,4]

phi beta kappa meaning?

philosophy is the guide of life

Write a function length that finds the length of a linked list with a new node

function length (head) { let length = 0; let current = head; while (current) { current = current.next; length++; } return length; }

KDE

Desktop environment for Linux

Multichannel memory architectures (RAM)

Dual channel, Triple Channel

TTY

the name of terminal session that the process is running within (shell)

Invoking a Function with an object Constructor

Closures and <this>

It is important to take note that closures cannot access the outer function's this variable by using the this keyword because the this variable is accessible only by the function itself, not by inner functions.

ksh

Korn shell is an early shell similar to csh

What are the three core components of NodeJS?

Libuv, V8 Engine, C++/JS Custom Code

Red vertical line in timeline?

Load

1024 - 49151

Registered Ports

Execution control buttons

Resume, Step over, Step into, Step out of, deactivate Breakpoints

special permissions

SUID : 4 SGID : 2 Sticky Bit : 1

Cache RAM

Static Ram, faster than regular system RAM. L1 , L2, L3

/etc/passwd

Stores linux user accts

Miami's chapter was called what until 1868

The Grand Chapter

String.prototype.includes()

The includes() method determines whether one string may be found within another string, returning true or false as appropriate. str.includes(searchString[, position])

Array Accessor methods

These methods do not modify the array and return some representation of the array.

System processes & Daemons

User Processes are tied to a particular shell instance , ystem processes ar enot.

: groupmod

modify a group's properties, GID number, c=group passwd, add a user account to the group, -R removes a user account from the group

Has the line that you set a breakpoint on been run?

push()

pushes an item onto the end of an array

Take the string "1234" and break it into an array of numbers

s.split('').map(Number);

runlevel 3

text-based environment

write (save) the file, but don't exit

How to fill first byte with 1's to a variable x?

x |= (0xFF)

var foo = function bar() { ... } --> what type of function?

NAMED FUNCTION EXPRESSION

Mono

NET OS version -- server side apps on Linux servers

E Minor

1 Sharp - F#

What is the structure of node objects in the DOM typically compared to?

A Tree

Constructor definition

A method called at the moment an object is instantiated. It usually has the same name as the class containing it.

What is an octet? Why do we use the term?

An octet is a unit of digital information in computing and telecommunications that consists of eight bits. The term is often used when the term byte might be ambiguous, since historically there was no standard definition for the size of the byte.

Associative Property

The word "associative" comes from "associate" or "group";the Associative Property is the rule that refers to grouping. For addition, the rule is "a + (b + c) = (a + b) + c"; in numbers, this means 2 + (3 + 4) = (2 + 3) + 4. For multiplication, the rule is "a(bc) = (ab)c"; in numbers, this means 2(3×4) = (2×3)4. Any time they refer to the Associative Property, they want you to regroup things; any time a computation depends on things being regrouped, they want you to say that the computation uses the Associative Property.

Always, what is <this>

This is the value of the object that invokes the function where this is used.

Import a constructor from a module named Bar

const Bar = require('bar'); notice the casing

Import a single property bar of a module named foo into a file

const bar = require('foo').bar;

search()

searches a string for text and returns an index position if found

: grep -r

searches recurisvely through subdirectories of the path specified

match()

similar to search, but sends back array of matched text instead of index position

Nth term of geometric series?

a_n = a_1 * r^(n-1)

: useradd

adds user. /etc/default/useradd contains defaults used by the useradd utility, including basic group, umask, etc.

Write a function that doubles each char in a given string using split,map,join

const doubleChar = (str) => str.split("").map(c => c + c).join("");

Import a module foo in the subdirectory bar

const foo = require('./bar/foo');

Import a node module named foo into a file

const foo = require('foo');

Konqueror

default KDE web browser

/etc/sysconfig/network/routes

default ateway router address is stored here

bash

default shell on linux

/etc/nsswitch

configures which services are to be used to resolve hostname and to store users groups, and passwords

why use console.log with a comma and not a +

console.log("my name is ", name); the + stringifies an object. if name is an object this is not quite what we want as we'll get "[object Object]"

Two ways of running shellscripts

call shell then script to execute -- bash ./runme, the second option is to give execute permissions to the file nd then run it with the path to the script

What are the 2 predefined function methods by which we can invoke a function?

call() and apply() are predefined JavaScript function methods.

Flash Memory

can be electronically erased and reprogrammed

DOCUMENT_FRAGMENT_NODE

e.g. document.createDocumentFragment() The DocumentFragment interface represents a minimal document object that has no parent. It is used as a light-weight version of Document to store well-formed or potentially non-well-formed fragments of XML. DocumentFragments allow developers to place child elements onto an arbitrary node-like parent, allowing for node-like interactions without a true root node. Doing so allows developers to produce structure without doing so within the visible DOM -- an increase of speed is the true advantage. Let me show you how DocumentFragments are used!

var globalObject = this; var foo = (() => this); what is the value of foo() ?

globalObject;

How do event handlers work?

http://stackoverflow.com/questions/7575589/how-does-javascript-handle-ajax-responses-in-the-background/7575649#7575649 it uses a queue - event loop other systems often use the polling mechanism and/or observer pattern

.bash_history

hwere ur bash history is stored

why not use nationals

incorrect usage since 1902 when PDT installed its first Canadian chapter at McGill Uni in Quebec. PDT should be referenced as the General or International headquarters (1902) (1902)

$MANPATH

path to system's man program

first greek letter organization?

phi beta kappa

SXGA+

1280 * 1024

WXGA

1280x720

Michael Stittgen

1367

Tze Ern Teo

1368

Keenan McKenzie

1369

Chethan Reddy

1370, VP Awards Chair

Sam Zacher

1376

Tyler Wojak

1377

James Taylor

1378

Andoni Garcia

1379

Bryan Bunning

1382, Treasurer

Jeremy Harvey Brown

1384, Warden

Jack Uidl

1391

Francis Beach

1392

Andrew Kilbourne

1393

Colin Findley

1394

Cristian Saucedo

1401

Justin Boganey

1403

Duncan McGillivary

1410, Alumni Secretary

Mantim Lee

1411

Ferdinand Chan

1412, Scholarship Chair

Pierre Danly

1414, Public Relations Chair, Co-Social Chair

Daniel Trainor

1416, House Manager

Luke Wilson

1417, Fundraising Chair

Kevin Yin

1419

Carter Brown

1421, Risk Manager

Kevin Brennan

1425, IM Sports Representative

Alex Espinosa

1426, House Tech

Jack Haggerty

1427

Kyle Lee

1429, Ex-Comm member at large

IMAP

143

Haskell: how to convert infix operator to prefix?

2 + 2 ---> (+) 2 2

stderr

2 -- error code or any serror message generated

C# Minor

4 Sharps - F# C# G# D#

E Major

4 Sharps - F# C# G# D#

Floppy plugs?

4-pin mini BERG

PATA plugs?

4-pin molex, 40-pin IDE ribbon

Size of manual

4.5" x 6" and 54 pages

DVD-ROM can hold up to?

4.7 GB

Number of provinces now?

HTTPS

443

USB 2.0

480 Mbps, 5 meters

Dynamic Ports & Private Ports

49152 - 65535 - designed as dynamic ports and are available for use by any network service. Frequently used by network services that need to establish a temporary connection. For example, aservice ma ynegotiate a dynamic port with the client. It wielll then use tha tport just during the current session when session is completed, port is closed and no longer used,

console.log([4, 5, 8, 12].find(isPrime));

Bb Minor

5 Flats - Bb Eb Ab Db Gb

Db Major

5 Flats - Bb Eb Ab Db Gb

50 % 100

Golden Legion

50 years Phis

Blu-RAy can hold up to?

50GB

802.11g

54Mbps 2.4Ghz

Input Output Ports - System Resource

5535 port available, all devices must have addresses, and must use unique I/o range.

USB 3.0

5Gbps

Eb Minor

6 Flats - Bb Eb Ab Db Gb Cb

Gb Major

6 Flats - Bb Eb Ab Db Gb Cb

D# Minor

6 Sharps - F# C# G# D# A# E#

F# Major

6 Sharps - F# C# G# D# A# E#

802.11n

600Mbps, 5 & 2.4Ghz

IEEE1394 devices?

SCSI plugs?

68 pin, 80 pin or serial

Cb Major

7 Flats - Bb Eb Ab Db Gb Cb Fb

A# Minor

7 Sharps - F# C# G# D# A# E# B#

C# Major

7 Sharps - F# C# G# D# A# E# B#

CD-ROM can hold up to?

700MB

Cost function vs Gradient Descent?

A cost function is something you want to minimize. For example, your cost function might be the sum of squared errors over your training set. Gradient descent is a method for finding the minimum of a function of multiple variables. So you can use gradient descent to minimize your cost function. If your cost is a function of K variables, then the gradient is the length-K vector that defines the direction in which the cost is increasing most rapidly. So in gradient descent, you follow the negative of the gradient to the point where the cost is a minimum. If someone is talking about gradient descent in a machine learning context, the cost function is probably implied (it is the function to which you are applying the gradient descent algorithm).

explain *new*

A new object is created, inheriting from Foo.prototype. The constructor function Foo is called with the specified arguments, and with this bound to the newly created object. new Foo is equivalent to new Foo(), i.e. if no argument list is specified, Foo is called without arguments. The object returned by the constructor function becomes the result of the whole new expression. If the constructor function doesn't explicitly return an object, the object created in step 1 is used instead. (Normally constructors don't return a value, but they can choose to do so if they want to override the normal object creation process.)

CMD: update

A utility for flushing file system buffers

Subshells

Always occur -- a subshell is created -- it is a separate process in and of itself and has its own PID assigned. the PPID of the subshel is the PID of the shell where command was entered. This process is called forking

function multiply(a, b = 1) { return a*b; } multiply(5); // 5 What ES6 feature does this demonstrate?

Default parameters

USB device categories

Hubs, functions, hub and function devices

What is "this" keyword for?

In JavaScript, the thing called this, is the object that "owns" the current code.

inflection points

In differential calculus, an inflection point, point of inflection, flex, or inflection (inflexion) is a point on a curve at which the curve changes from being concave (concave downward) to convex (concave upward), or vice versa. A point where the curvature vanishes but does not change sign is sometimes called a point of undulation or undulation point.

What is <this> in the global execution context?

In the global execution context (outside of any function), this refers to the global object, whether in strict mode or not. (console.log(this.document === document); // true // In web browsers, the window object is also the global object: console.log(this === window); // true this.a = 37; console.log(window.a); // 37 )

First FP programming language?

Lisp -- this is important because Lisp is often used as a good comparison and frequently referenced.

Array.prototype.copyWithin() ECMASCRIPT 6 (need to put in more examples for this one)

MUTATOR METHOD The copyWithin() method shallow copies part of an array to another location in the same array and returns it, without modifying its size.

Array.prototype.splice()

MUTATOR method Adds and/or removes elements from an array.

Array.prototype.push()

MUTATOR method Adds one or more elements to the end of an array and returns the new length of the array.

Array.prototype.unshift()

MUTATOR method Adds one or more elements to the front of an array and returns the new length of the array.

Array.prototype.fill()

MUTATOR method Fills all the elements of an array from a start index to an end index with a static value.

Array.prototype.shift()

MUTATOR method Removes the first element from an array and returns that element.

FOSS - Free and Open Source S

Overcome division between OSI and FSF by not labeling software as open source

Value of <this>: function f1(){ return this; }

Window object. In this case, the value of this is not set by the call. Since the code is not in strict mode, the value of this must always be an object so it defaults to the global object.

What is the advantage of using call and apply methods?

With call() or apply() you can set the value of this inside the function and invoke the function as a new method of an existing object.

zsh

Z shell is improved version of bash

Firstfraternity to expand into canada

Zeta Psi, University of Tornoto 1879

var x = "YOLO"; return x.split('');

["Y","O","L","O"];

var x = "YOLO"; return x.split();

["YOLO"];

"moon".match(/\bm/)

["m"]

"at noon".match(/\Bon/)

["on"]

scp

a utility that securely copies files between systems

var foo = function bar() { // statements go here }; What are the three ways to recursively call this named function expression?

bar() arguments.callee() foo()

etc/X11/xorg.conf

conf for xorg

$HISTSIZE, $HISTFILESIZE

configconfigs size of history file -- default 1000

/etc/exports

configures file systems oto be exported to remote NFS clients

: ifconfig

displays the current status fo all network interfaces in the system

So you just selected three elements in order a, div, h1 and in console you do $1 what do you get back?

div

body

document data displayed to users by client browser

In Javascript/jQuery what does (e) mean?

e is the short var reference for event object which will be passed to event handlers. The event object essentially has lot of interesting methods and properties that can be used in the event handlers. jQuery's event system normalizes the event object according to W3C standards. The event object is guaranteed to be passed to the event handler. Most properties from the original event are copied over and normalized to the new event object.

:echo

echo line of text

etc/grub.conf or /boot/grub/grub.conf

edit the boot menu

what arguments does Array.prototype.forEach callback accept?

element, index, array (callback is invoked with three arguments: the element value the element index the array being traversed)

What statements does ASI affect?

empty statement var statement expression statement do-while statement continue statement break statement return statement throw statement (http://stackoverflow.com/questions/2846283/what-are-the-rules-for-javascripts-automatic-semicolon-insertion-asi)

CommonJS fixes what problem

encapsulation of modules and ability to connect with other modules.

Window Managers

enlightenment, fvwm, kwin, sawfish, twm, wmaker

: egrep

grep seearch files for extended regexps.

: host

host command to resolve hostnames whereas dig provides extensive name resolution info host provides quick info the syntax is ismilar to dig. you enter host hostname DNS_server at shell prompt -- shows quick info -- very useful

$HOST and $HOSTNAME

hostname of system when installed

Accepted reply to formal intros

how do you do

Privileged vs Private vs Public

http://javascript.crockford.com/private.html Public function Constructor(...) { this.membername = value; } Constructor.prototype.membername = value; Private function Constructor(...) { var that = this; var membername = value; function membername(...) {...} } Note: The function statement function membername(...) {...} is shorthand for var membername = function membername(...) {...}; Privileged function Constructor(...) { this.membername = function (...) {...}; }

lo interface

local loopback virtual network interface -- required for many linux services DONT TINKER

Local vs LDAP

local stores at /etc/passwd. LDAP(Lightweight Directory Access Protocol) Unlike local authentication which stores accounts in a simple flat file, the directory service is hierarchical in natre; allowing you to sort and organize your user accounts by location, function, or department. The directroy database can also be replicated among several different Linux systems providing fault tolerance. The key benefit of this option is that it allows yout o maintain a single set of user accounts that can be used to authenticate to many different Linux systems in your network.

$DISPLAY

location where Xwindow dispaly should be sent

/var/log/faillog

log files contains a list of failed authentication attemp --- effective at detecting dictionary attacks which run through a list of words. view it using the fiallog utility -- faillog - u rtracy

CMD: logout

log out command

var myConstructor = function () { this.someMethod = function () { console.log(this); }; }; var a = new myConstructor(); a.someMethod(); what does someMethod(); put out?

myConstructor();

GIMP

open source to Adobe Photoshop

Cathedral Model

organized software development structure - less collaborative and more structured -- restricted to a group of specific programmers for a particular OS project. Source is still released. During dev it's limitd

: nl

output is written with a line number added to beginning of each line in the file

{1,3}

preceding expression 1 to 3 times

{3}

preceding expression 3 times

What is Phi Beta Kappaa today

prestigious honor society

echo

print some arguments

: wc

prints the number of newlines, words, and bytes, depending on flags -c byte -m character -l newline -L length of longest line -w print word counts

What is the equivalent to the global object, Window, in Node?

process

Document.querySelector(String selector)

returns the first element node within the document in document order that matches the specified selectors.

undefined vs not defined?

undefined is a type, the following error often pops up when trying to use something that just does not exist at all "var name is not defined"

: chown

used to change user or group that owns a fiel or directory chown user.group file or directory -R change ownership recursively

: head

used to display first couple of lines of a text file on screen

: pr

used to format text files for printing -- determine margins, etc

Write a file my-module.js that exports a default function cube! Then import it in another file. Use Default Exports

// module "my-module.js" export default function cube(x) { return x * x * x; } import cube from 'my-module'; console.log(cube(3)); // 27

System Resources

IRQ, Input/output ports, DMA Channels, PNP

What is the page object in a browser?

In a browser the page object is the browser window. The function above automatically becomes a window function.

Array.prototype.reverse()

MUTATOR method Reverses the order of the elements of an array -- the first becomes the last, and the last becomes the first.

$BASH $SHELL

full path to shell executable

get by more than

gentleman's c grade

ES6: var a = 5; var b = 10; console.log("Fifteen is " + (a + b) + " and\nnot " + (2 * a + b) + "."); // "Fifteen is 15 and // not 20." rewrite using ES6 template literals

var a = 5; var b = 10; console.log(`Fifteen is ${a + b} and\nnot ${2 * a + b}.`); // "Fifteen is 15 and // not 20."

First manual was printed when

1886

Don't Criticize, Condemn, or Complain - Benjamin Franklin

I will speak ill of no man, and speak all the good I know of everybody

What is the defult global object in HTML?

In HTML the default global object is the HTML page itself, so the function above "belongs" to the HTML page.

What is the only difference between apply() and call() methods?

The only difference is that call() takes the function arguments separately, and apply() takes the function arguments in an array.

Dynamic address assignment

a netowork host contacts a DHCP server when it boots. the DHCP server dynamically assigns an IP address to the host for a psecified period of time called a lease. It allows IP configuration for a large # of network hosts very easy. Just power the system on and it gets its IP address information. t also conservs IP address usage. Addresses used by systems that are powered off can be reassigned to other network hosts.

How to get away from the table?

a nod and "May I be excused"

/etc/init.d

a subdirectory that contains startup scripts for services intalled on the system. Ona Fedora or a RH stsytem, these are located in /etc/rc.d/init.d

Postfix

a very widely used mail transfer agent on a Linux server to provide email servers

a {} block (with brackets)

Find nth term of an arithmetic sequence?

a_n = a_1 + (n-1)d

Nth term of arithmetic sequence?

a_n = a_1 + (n-1)d

: route add -net 192.168.2.0 netmask 255.255.255.0 gw 192.168.1.254

add a route to the network through router with ip address of 192.168.1.254

Subnet masks aresometimes noted using a shorthand

add a slash and the number of bits that are used for subnet mask /24 would be a class C address.

: route

add routes to the table by entering route add-net network_address netmask netmask gw router_address

VI: C

changes characters in the current line until ESC is hit

VI : cw

changes replaces current word with new text, starting with character until cursor until esc is hit

VI : cc

changes, replaces entire current line, until ESC is hit

/etc/aliases

contains table used to redirect mail to local recipients

CPU

contains transistors uses binary to calcualte

/etc/login.defs

contains values that cna be used for the GID AND UID params when creating an cct with useradd, also contains defaults for creating pass2words in /etc/shadow.

/Videos

contains video files

warn

contains warning messages

why use features that are on a similar scale?

contour plots with differently scaled features will be extremely thin or extremely fat resulting in a very slow gradient descent (convergence is slower) get them to a -1 <= x <= 1 scale. poorly scaled is too large -100 to 100 or -0.00001 or 0.00001

VI: dw

delete word that comes immediately after cursor, text is saved to mem buffer

Write a function that <always> that takes an input <n> and returns a function which returns <n>

function always(n) { return function(){ return n; } }

Write a function makeAdder(x) using closures that returns a function that adds any value to x.

function makeAdder(x){ return fuction(x,y){ return x+y; }; } var add5 = makeAdder(5); var add10 = makeAdder(10); console.log(add5(2)); // 7 console.log(add10(2)); // 12

go through thsi...

mark a word

User variables

only available to the current instance of shell by default

valueOf()

returns the primitive value of the String object

designer of pin

robert morrison, miami-ohio 1849

/pattern

search for pattern

Why not say house instead of chapter

smoe chapters dont have houses

split()

splits a string and returns an array of substrings

What do we make from a function with call and apply?

we make a method for an existing object. we envoke the function which becomes a method of an existing object because among the arguments we define the object to which the funcion will belong

www.rpmfind.net

website to find Open source packages

D Major

2 Sharps - F# C#

[1, 2, 3, 4, 5].copyWithin(-2, -3, -1);

[1, 2, 3, 3, 4]

[1, 2, 3].fill(4, 1, 2);

[1, 4, 3]

sftp

a utility that securely ransfers files between systems

Invoking a Function as a Method

Invoking a Function with a Function Method

What if we invoke a function as a global function?

Invoking a function as a global function, causes the value of this to be the global object.

What will be the value of "this" inside the code block of the function if we Invoke the function as the method of an object?

Invoking a function as an object method, causes the value of this to be the object itself.

(C++) How are private and protected members different from public properties?

It is important to note that private and protected members can not be accessed directly using direct member access operator (.). We will learn how private and protected members can be accessed. (#include <iostream> using namespace std; class Adder{ public: // constructor Adder(int i = 0) { total = i; } // interface to outside world void addNum(int number) { total += number; } // interface to outside world int getTotal() { return total; }; private: // hidden data from outside world int total; }; int main( ) { Adder a; a.addNum(10); a.addNum(20); a.addNum(30); cout << "Total " << a.getTotal() <<endl; //60 return 0; }) Note that this is called encapsulation.

Become genuinely interested in people - Alfred Adler

It is the individual who is not interested in his fellow men who has the greatest difficulties in life and provides the greatest injury to others. It is from among such individuals that all human failures spring.

Tail Recursion with Accumulators reason

It's unnecessary to keep around a stack frame when it is just going to return a value. Some compilers will optimize for this by using the same stack space if the return values are the same. It is reasonable to assume all functional-language implementations optimize these tail calls. -- So there's less memory used, and it is faster overall.

For a sufficiently small alpha...

J(Theta) should decrease EVERY iteration

What does the JQuery $ return?

JQuery Object contains array of elements.

Match digit character (Equivalent to [0-9]. For example, /\d/ or /[0-9]/ matches '2' in "B2 is the suite number.")

/etc/inittab

configures the type of environment loaded (runlevel configs)

console.log("string text line 1\n"+ "string text line 2"); rewrite this using ES6 template literals

console.log(`string text line 1 string text line 2`);

/etc/hosts

contains a list of hostname-to-IP address mappings the system can use to resolve hostnames

wtmp

contains a list of users who have authenticated to the system

boot.msg

contains all of the messages dispalyed on screen during system bootup -- useful for trobuleshoooting startup problems

∋

contains as a member, "ni"

/etc/modules.conf

contains config parameters for your kernel modules (drivers)

/etc/grub.conf

contains config parameters to the GRUB bootloader

/etc/inittab

contains configuration paramters for the init process

/Documents

contains documents

/etc/shadow

contains encrypted passwords for your caccounts

firewall

contains firewall log entries

/Pictures

contains image files

lastlog

contains last login info for users

/etc/group

contains local group definitions

xinetd.log

contains log entries form the xinetd daemon

boot.log

contains log entries from daemons as they were started during bootup

messages

contains messages from most running porcesses -- probably the most useful of all log files - used to torubleshoot services that wont start services taht dont appear tow ork properly

mail

contains messagesgnereated by the postfix or sendmail daemons

/Music

contains music files

/public_html

contains personal web pages

/etc/bashrc or /etc/bash.bashrc

contains shell system-wide functions and aliases

/etc/profile /etc/profile.d

contains system wide shell env config paramenters

VI: dd

deletes entire line, text saved to a memory buffer

VI: d$

deletes from insertion point to end of line, text is saved to a memory buffer

VI : D

deletes rest of current linefrom cursor position

VI: de

deletes word that comes immediately after cursor but not including space, text is saved to mem buffer

/var/log/messages

detect intrustion attempts -- contains messages from all srvices running on the system --

/srv

directory contains subd's where services running on system such as httpd, and ftpd save files

: netstat

dispalys status of network, current connectiosns, routing table,s, and so on

: env

display environment variables

: ps -ef

display extended information of all (-e) processes running.

: tail

display las tcouple of lines the -f flag is very powerful

: whoami

display s username of currently logged in user

: grep -v

displays all lines that DO NOT contain the search string.

: which

displays full path to a shell command or utility

CMD: SaX2

displays interface that u can use to configure ur video subsystem

: top

displays list of all apps and processes, sortable

: grep -n

displays matching line numbers

: grep -l

displays on names of files that ocntain matching text

: >>

doesnt overwrite, appends

What are the mutative array functions in Javascript?

push, pop, shift, unshift, sort, reverse, splice and delete (kind of).

quit (fails if anything has changed)

:q!

quit and throw away changes

What does theta typically represent in stat/ML?

quite often θ stands for the set of parameters of a distribution.

CMD: reboot

reboots the system

replace()

receives 2 arguments, first the string to be replaced, then the replacement text

: >

redirection of stdout

rc.d and init.d

stop and run these scripts within rc.d or init.d

~/.bashrc

stores user-specific functions and aliases

/opt

this directory cotains files for some prorgams you install on the system

/proc

this directory is a little diff from the other d's in this list, /proc doesnt actually exist in the file system. It's a pseuudo-file system taht's dynamically created whenever access. -- The "top" program uses this folder.

/media

this directory is usedby some linux distros such as OpenSUSE and fedora to mount external devices, including optiacal drives, USB drives, etc . This is done using a series of subd

/lib

this directory ocntains code libraries used by programs in /bin and /sbin. Your kernel modules are also stored in the modules subdirectory of /lib

/etc/shadow

this file contains password for your user accounts

AJS: (function ($) { $(document).ready(function () { // my code }); })(jQuery);

this technique is used to rename different globals appropriately, i.e. conflict of prototype and JQuery using $

: info (cmd)

this will give u a longer description of the command

How to access component properties?

this.props

Morrisons philosophy

to do what ought to be done but what would not ahve been done unless i did it, i thought to be my duty

What is the purpose of the DOM?

to provide a programatic interface for scripting (removing, adding, replacing, eventing, modifiying) this live document using JavaScript.

: ps -e

to see all processes running on system

: top

top provides variety of tools for viewing runnin gprocesses on yourr system. pressing H gets help screen F displays other columns you can add

Physical LAyer

transmits electrical signals between hosts

transpose two letters (delete and paste, technically)

3DES

triple data encryption standard -- symmetric encryption used to encrypt data in three stages in either a 112 bit or 168 bit key

JS: 1 + 2 > 3

true

[3].every(a => a = 3);

true

friendship

true friendship, for one who strives to act maturely, will raise thq uestion - what can i give, rather than what is in it for me?

classical authors mention the duties of friendship

truthfulness, mutual correction, fidelity.

: w

what proccesses are the people who are logged in running?

[x[y]]

when x is provided y is optional

/lib/modules/kernel_version/kernel/drivers

where drivers and kernel modules are stored

: whereis

whereis locates source code, binary files, and man pages for specified files -b for binary path -m for man pages

while loop

while condition do script commands done

trim()

white space is removed from both sides of string original string is not altered

when does a stream stop writing

whitespace encounter

Haskell: whitespace is not significant in Haskell T or F?

whitespace is significant in Haskell

: who

who is logged on?

DOCUMENT_NODE example?

window.document

Check for even or odd number using bits

x&1 ? "odd" : "even"

var account = require('./myModule2.js')(2000);what is this code doing in relation to CommonJS

you can assume that the module being imported or required is a constructor/class, and by invoking the constructor we're creating a class instance

partial subnetting

you could define a subnet mask of 255.255.252.0 for a class B address.

How do you change the sign of an integer?

~x + 1

cat

print the whole file

pwd

print working directory

let animals = [{name: "cow", qty: 2}, {name: "pig", qty: 2}]; return animals.find( (animal) => animal.qty === 2);

{name: "cow", "qty: 2}; (find returns first value in the array found, the value here is an object)

Unminifying in DevTools

{} button on bottom

JS Precedence: Logical AND vs Logical OR && vs ||

Telnet

Silver Legion

25 years Phis

navigate until second "x" character

2fx

100 % 101

100

Add a "//" to multiple lines at once

<C-v> + I + // + esc

Carriage Return

JQUERY: event.type

Describes the nature of the event. -- mouseclick,

Blue vertical line in timeline?

DOMContentLoaded

pandas.DataFrame.fillna

Fill NA/NaN values using the specified method - returns the filled DataFrame

What datatype is a function in js?

In JavaScript, functions are objects.

GRUB & GRUB2

Manager of the bootmenu and bootloader

IBM Expansion Slots

Modular PCI & PCIe model

Pidgin

Open Source IM

ctrl+wq

Quit a window

X Window System, X11, X

Window manager

when was pdt founded

december 26, 1848

end of line

three cardinal rules

friendship, sound learning, rectitude

move down

USB

serial bus

Blowfish

variable key lengths up to 448 bits

What is put out by myFunc(); function myFunc() { console.log(this); }

window object

word boundary. (Matches a word boundary. This is the position where a word character is not followed or preceded by another word-character, such as between a letter and a space. Note that a matched word boundary is not included in the match. In other words, the length of a matched word boundary is zero.)

:wq

write (save) and quit

Method vs function invocation

x.a() vs a(x) (""the method-invocation syntax is an elegant way to express the fact that function is operating on an object");

yank (copy) marked text

2yy

yank 2 lines

yank to end of line

yank word

Do arrow functions with no params require parens?

yes

Do arrow functions with two* params require parens?

yes

Does the order of operations matter in Matrices?

yes

Haskell: Are functions first class citizens?

yes

Triangle Inequality Theorem not including zero area triangles, x, y, z sides

z < x + y

telephone etiquette

"Phi Delta Theta, how may I help you?"

Smile - Shakespeare

"There is nothing either good or bad, but thinking makes it so"

example of test flag

"[-e "$MYNEWPATH"]; if test -f /home/rtracy/myfile; then echo.

write a regex with brackets for a character between A through F or a through t (lowercase) and 0 through 4

/[A-Fa-t0-4]/

Simplify 2(3x), and justify your steps.

2(3x) original (given) statement (2×3)x by the Associative Property 6x simplification (2×3 = 6)

FTP

SSh

ATX 12v 2.x Power conects with what cables

24 pin cable + 4pin for CPU and 6 or 8 pin for video

DDR2/DDR3 pns

240

SMTP

delete until second "x" character

2dfx

function outside(x) { function inside(y) { return x + y; } return inside; } fn_inside = outside(3); result = fn_inside(5); Value of result?

Db Minor

8 Flats - Bbb Eb Ab Db Gb Cb Fb

Fb Major

8 Flats - Bbb Eb Ab Db Gb Cb Fb

G# Major

8 Sharps - F## C# G# D# A# E# B#

hTTP

IEEE1394b

800Mbps, 1600Mbps, 3200 Mbps

Haskell: how to get type of expression in GHCI?

:type expr

DOCUMENT_TYPE_NODE

<!DOCTYPE html>

String comparison - strcmp equivalent?

<, > var a = 'a'; var b = 'b'; if (a < b) { // true console.log(a + ' is less than ' + b); } else if (a > b) { console.log(a + ' is greater than ' + b); } else { console.log(a + ' and ' + b + ' are equal.'); }

ELEMENT_NODE example?

Closure definition

(Closures are one of the most powerful features of JavaScript. JavaScript allows for the nesting of functions and grants the inner function full access to all the variables and functions defined inside the outer function (and all other variables and functions that the outer function has access to). However, the outer function does not have access to the variables and functions defined inside the inner function. This provides a sort of security for the variables of the inner function. Also, since the inner function has access to the scope of the outer function, the variables and functions defined in the outer function will live longer than the outer function itself, if the inner function manages to survive beyond the life of the outer function. A closure is created when the inner function is somehow made available to any scope outside the outer function.)

What is wrong with this code sample? var person = { firstName: "Penelope", lastName: "Barrymore", fullName: function () { // We could have also written this: console.log(person.firstName + " " + person.lastName); } }

(If we use person.firstName and person.lastName, as in the last example, our code becomes ambiguous. Consider that there could be another global variable (that we might or might not be aware of) with the name "person." Then, references to person.firstName could attempt to access the fistName property from the person global variable, and this could lead to difficult-to-debug errors. ) Use this.firstName and this.lastName instead.

Tail Call

(In computer science, a tail call is a subroutine call performed as the final action of a procedure. If a tail call might lead to the same subroutine being called again later in the call chain, the subroutine is said to be tail-recursive, which is a special case of recursion. Tail recursion (or tail-end recursion) is particularly useful, and often easy to handle in implementations.)

Gradient Descent for linear regression?

(Review again)

What are simple patterns in regular expressions?

(Simple patterns are constructed of characters for which you want to find a direct match. For example, the pattern /abc/ matches character combinations in strings only when exactly the characters 'abc' occur together and in that order. Such a match would succeed in the strings "Hi, do you know your abc's?" and "The latest airplane designs evolved from slabcraft." In both cases the match is with the substring 'abc'. There is no match in the string 'Grab crab' because while it contains the substring 'ab c', it does not contain the exact substring 'abc'.)

Tail Call Elimination

(Tail calls can be implemented without adding a new stack frame to the call stack. Most of the frame of the current procedure is not needed any more, and it can be replaced by the frame of the tail call, modified as appropriate --similar to overlay for processes, but for function callsThe program can then jump to the called subroutine. Producing such code instead of a standard call sequence is called tail call elimination. Tail call elimination allows procedure calls in tail position to be implemented as efficiently as goto statements, thus allowing efficient structured programming.)

Why is Function.prototype.apply() useful?

(There are often cases where a function needs to be called dynamically, or the number of arguments to a function vary, or in which the context of the function call needs to be set to a specific object determined at runtime. )

Haskell: Select 2nd element of a list

[1,2,3,4,5] !! 2 note that this is not a constant time operation because lists are not arrays in Haskell

AJS: IIFE syntax ways

(function(){ /* code */ })(); - ben alman and many others (function(){ /* code */ }()); - crockford

How to check if a number is a power of two?

(n & (n - 1)) == 0 this works because every power of 2 has just one 1 in binary

Array.prototype.sort([5,10,14]);

[10,14,5] (Array.prototype.sort mutates and returns the mutated array, but it sorts based on Unicode value)

Synchronous vs Asynchronous code?

//example 1 var result = database.query("SELECT * FROM hugetable"); console.log("query finished"); console.log("Next line"); //example 2 database.query("SELECT * FROM hugetable", function(result) { console.log("query finished"); }); console.log("Next line"); query finished Next line Next line query finished

Scalar official definition?

(of a quantity) having only magnitude, not direction.

saying for caret and dollar?

(you farm carrots to make dollars. so the ^ indicates beginning, the $ indicates the end of input.)

regexp quick overview

* ? . ^ $ | [nnnn] [^nnnn] [n-n] | matches characters on either side of the pipe [nnn] any one of the characters [^nnn] not containing any of the characters [n-n] containing anything within that range

Define the properties of two matrices and those particular of square matrices

*All Matrices* Not commutative, Distributive over matrix addition Scalar multiplication is compatible with matrix multiplication, Transpose Complex Conjugate Conjugate Transpose Traces *Square Matrices* Identity Element - If A is a square matrix, then AI = IA = A where I is the identity matrix of the same order. Inverse Matrix - ?? Determinants - if A and B are square matrices of the same order, the determinant of their product AB equals the product of their determinants:

JS Precedence: Greater Than vs Addition > vs + e.g. 1 + 3 > 3

Write a file my-module.js that exports a function Cubed and a const foo. Then import the two into another file. Use Named Exports

// module "my-module.js" export function cube(x) { return x * x * x; } const foo = Math.PI + Math.SQRT2; export { foo }; -------- import { cube, foo } from 'my-module'; console.log(cube(3)); // 27 console.log(foo); // 4.555806215962888

Create a global namespace called MYAPP, then create a sub namespace called event

//global namespace var MYAPP = MYAPP || {}; // sub namespace MYAPP.event = {};

Simulate the processing of the following code: function foo(){ function bar() { return 3; } return bar(); function bar() { return 8; } } alert(foo());

//**Simulated processing sequence for Question 1** function foo(){ //define bar once function bar() { return 3; } //redefine it function bar() { return 8; } //return its invocation return bar(); //8 } alert(foo());

Simulate the processing of the following code: function foo(){ var bar = function() { return 3; }; return bar(); var bar = function() { return 8; }; } alert(foo());

//**Simulated processing sequence for Question 2** function foo(){ //a declaration for each function expression var bar = undefined; var bar = undefined; //first Function Expression is executed bar = function() { return 3; }; // Function created by first Function Expression is invoked return bar(); // second Function Expression unreachable } alert(foo()); //3

sound learning

- comes oabout only if one has the will to study and the dirsire to penetrate beyond the surface, genetleman's c grade

arguments object

- not an array but array-like - good to do conditionals based on number of arguments - .length property - variable number of parameters (function myConcat(separator) { var args = Array.prototype.slice.call(arguments, 1); return args.join(separator); })

console.log([4, 6, 8, 12].findIndex(isPrime));

-1

Nice value range

-20 to +19

flags that test for files

-e check if exists, -d check to see if dir exists -f check to see if file exists and is a regular file -G check to see if specified file exists and is owned by aspecified group -h or -L checks to see if specified file exists and if it is a symbolic link. -O checks to see if specified file exist & if it is owned by a specified user Id -r checks to see if specified file exists and if read permission is granted -w checks to see if specified file exists and if write permission is granted -x checks to see if specified file exists and if execute permission is granted

: uname flags

-s Display kernel name -n display system hostname -r kernel release number -v kernel version number -m system hardware architecture -p processor type -i display shardware platform -o displays os -a displays all

Add one to n using bit ops

-~n

When is Matrix Multiplication commutative?

... one matrix is the Identity matrix. ... one matrix is the Zero matrix. ... both matrices are rotation matrices. (basically case #2) ... both matrices are Diagonal matrices.

What do we create with a constructor invocation? step 1

// This is a function constructor: function myFunction(arg1, arg2) { this.firstName = arg1; this.lastName = arg2; } A constructor invocation creates a new object. The new object inherits the properties and methods from its constructor. // This creates a new object var x = new myFunction("John","Doe"); x.firstName; // Will return "John"

configuring DNS

/etc/resolv.conf defines search prefix and nameserveers to use the search column specifies the domain name that should be used to fill out incomplete hostnames for example if yu were try to resolve a hostname of WS1 name would convert to FQDN of ws1.mydom.com namesearch field specifies IP address of DNS servers you want to use for name resolution you can configure up to 3 DNS servers if first server fails or is otherwise unreachable next DNS server is used syntax is nameserver DNS_server_IP_address

private key

/etc/ssh/ssh_host_key

public key

/etc/ssh/ssh_host_key.pub

Init process PID

The three rules and side effects of closures

1. Closures have access to the outer function's variable even after the outer function returns 2. Closures store references to the outer function's variables;

Javascript Closure Recipe

1. Create parent function 2. Define variables in parent's local scope. 3. Define a function inside the parent function i.e. child 4. Return the function from inside the parent function

What are the closure's scope chains?

1. It's own scope, variables defined within its own curly braces. 2. Access to outer function's variables and arguments. 3. Access to global variables.

PDT was the first to...

adopt a pledge pin and publish a pledge manual.

AJS: What are the four ways that the <this> keyword can be called?

1. New Keyword 2. Explicit/Hard Binding 3. Implicit Binding Rule: turns into the object that invoked the function -- o2 = {bar: "bar2", foo: foo}; 4 (least precedence). normal function call : default binding rule - if you are in strict mode, this is undefined if not, then this is the global object. 1. Default Binding - (catch all) - plain, un-decorated function reference - goes to global or undefined depending on strict mode settings 2. Implicit Binding - calling a function off an object obj1.foo() where foo can be defined anywhere - goes to the object that is calling it 3a. Explicit Binding - explicitly defining the this reference using call or apply ``` function foo(){ console.log(this.a); } var obj = { a: 2 }; foo.call(obj); ``` how does "boxing" work? 3b. Hard Binding - solves the possibility of explicit or any binding losing its intended binding - you can implement using Function.prototype.bind, a helper function, function wrapping or any other mechanism ``` function foo(){ console.log(this.a); } var obj = { a : 2; }; var bar = function(){ foo.call( obj); }; bar(); // 2 setTimeout(bar, 100); //2 bar.call(window); // 2 ``` 4. New Keyword - As a new object created via constructor call hijacking via "new"

Bb Major

2 Flats - Bb Eb

G Minor

2 Flats - Bb Eb

B Minor

2 Sharps - F# C#

Floppy size?

1.44MB

100 % 200

100

Registered Ports

1024 - 49151 - ICANN has reserved ports for speccial implementations . Organizations can program their own network service and then apply for a registered port number to be assigned to it.

XGA

1024 X 768

POP3

110

In 8-bit Two's Complement what is -1 in binary, what about -127?

1111 1111

802.11b

11Mbps 2.4Ghz

USB 1.1

12 Mbps, 3 meters

USB

127 deviceses

Max lenghth of a bash script

128 KB use

Class B

128-191

Commutative Property

3 * 2 = 2 * 3, 5 + 3 = 3 + 5 The word "commutative" comes from "commute" or "move around", so the Commutative Property is the one that refers to moving stuff around. For addition, the rule is "a + b = b + a"; in numbers, this means 2 + 3 = 3 + 2. For multiplication, the rule is "ab = ba"; in numbers, this means 2×3 = 3×2. Any time they refer to the Commutative Property, they want you to move stuff around; any time a computation depends on moving stuff around, they want you to say that the computation uses the Commutative Property.

C Minor

3 Flats - Bb Eb Ab

Eb Major

3 Flats - Bb Eb Ab

A Major

3 Sharps - F# C# G#

F# Minor

3 Sharps - F# C# G#

Volts of power supply

3.3v 5v 12v

How long was the Olympian of Phi Delta Theta

316 pages

How long was the olympian of pi delta theta

316 pages

RDP

3389

PATA

33MHz - 133MHz

Ab Major

4 Flats - Bb Eb Ab Db

DNS

// let's assume .elem is <div class="elem"></div> var element = document.querySelector('.elem'); var someMethod = function () { console.log(this); }; element.addEventListener('click', someMethod, false); What is put out on click?

<div class="elem"></div>.

Haskell: Generalizations of <head> and <tail>?

When a function is used as a constructor with the <new> keyword, what is the value of <this>

<this> is bound to the new object being constructed.

: ? shell variable

? shell variable to get the exxit status f the previously exited commmand. e.g. in a script use echo "Exit status is" $? ."

What is a Node?

A Node is an interface from which a number of DOM types inherit and allow these various types to be treated or tested similarly.

Namespace definition

A container which lets developers bundle all functionality under a unique, application-specific name.

What are contour plots?

A contour plot is a graphical technique for representing a #D surface by plotting constant z slices, called contours onto a 2Dimensional format. That is, given a value for z, lines are drawn for connecting the x,y, coordinates twhere that z value occurs. The circles in a contour plot are called level sets - the function J is equal here.The center of the contour plot is the minimum of the cost function typically in ML.

What is a Privileged Method?

A privileged method is able to access the private variables and methods, and is itself accessible to the public methods and the outside. It is possible to delete or replace a privileged method, but it is not possible to alter it, or to force it to give up its secrets.

What is the Christmas Tree problem?

A problem of asynchronous code due to severe nesting of callbacks.

Array.prototype.slice vs Array.prototype.slice is a good demonstration of what?

A pure function vs a non-pure function. arr.slice([begin[, end]]) --> begin is zero-indexed, end is zero-indexed but is not included in the slice. slice does NOT alter the given array. It returns a shallow copy of elements from the original array. array.splice(start, deleteCount[, item1[, item2[, ...]]]) --> start is the beginning index to start changing the array, deleteCount is the number of elements to delete, items are anything to be added var myFish = ['angel', 'clown', 'mandarin', 'surgeon']; // removes 0 elements from index 2, and inserts 'drum' var removed = myFish.splice(2, 0, 'drum'); // myFish is ['angel', 'clown', 'drum', 'mandarin', 'surgeon'] // removed is [], no elements removed // myFish is ['angel', 'clown', 'drum', 'mandarin', 'surgeon'] // removes 1 element from index 3 removed = myFish.splice(3, 1); // myFish is ['angel', 'clown', 'drum', 'surgeon'] // removed is ['mandarin'] // myFish is ['angel', 'clown', 'drum', 'surgeon'] // removes 1 element from index 2, and inserts 'trumpet' removed = myFish.splice(2, 1, 'trumpet'); // myFish is ['angel', 'clown', 'trumpet', 'surgeon'] // removed is ['drum'] // myFish is ['angel', 'clown', 'trumpet', 'surgeon'] // removes 2 elements from index 0, and inserts 'parrot', 'anemone' and 'blue' removed = myFish.splice(0, 2, 'parrot', 'anemone', 'blue'); // myFish is ['parrot', 'anemone', 'blue', 'trumpet', 'surgeon'] // removed is ['angel', 'clown'] // myFish is ['parrot', 'anemone', 'blue', 'trumpet', 'surgeon'] // removes 2 elements from index 2 removed = myFish.splice(myFish.length -3, 2); // myFish is ['parrot', 'anemone', 'surgeon'] // removed is ['blue', 'trumpet']

: route

A routing table is a set of rules, often viewed in table format, that is used to determine where data packets traveling over an Internet Protocol (IP) network will be directed. All IP-enabled devices, including routers and switches, use routing tables. A routing table contains the information necessary to forward a packet along the best path toward its destination. Each packet contains information about its origin and destination. When a packet is received, a network device examines the packet and matches it to the routing table entry providing the best match for its destination. The table then provides the device with instructions for sending the packet to the next hop on its route across the network. A basic routing table includes the following information: Destination: The IP address of the packet's final destination Next hop: The IP address to which the packet is forwarded Interface: The outgoing network interface the device should use when forwarding the packet to the next hop or final destination Metric: Assigns a cost to each available route so that the most cost-effective path can be chosen Routes: Includes directly-attached subnets, indirect subnets that are not attached to the device but can be accessed through one or more hops, and default routes to use for certain types of traffic or when information is lacking.

Array.prototype.slice()

ACCESSOR method Extracts a section of an array and returns a new array. arr.slice([begin[, end]]) *Shallow copy *End index is not included *There's an equivalent method for Strings, and slice works on Array-like objects i.e. arguments begin: Zero-based index at which to begin extraction. As a negative index, begin indicates an offset from the end of the sequence. slice(-2) extracts the last two elements in the sequence. If begin is undefined, slice begins from index 0. end: Zero-based index at which to end extraction. slice extracts up to but not including end. slice(1,4) extracts the second element through the fourth element (elements indexed 1, 2, and 3). As a negative index, end indicates an offset from the end of the sequence. slice(2,-1) extracts the third element through the second-to-last element in the sequence. If end is omitted, slice extracts through the end of the sequence (arr.length).

Array.prototype.join()

ACCESSOR method Joins all elements of an array into a string. join defaults to using ',' as a separator use .join('') to get a full string that is not delimited.

Array.prototype.indexOf()

ACCESSOR method Returns the first (least) index of an element within the array equal to the specified value, or -1 if none is found. arr.indexOf(searchElement[, fromIndex = 0])

Array.prototype.lastIndexOf()

ACCESSOR method Returns the last (greatest) index of an element within the array equal to the specified value, or -1 if none is found.

AmD Phenom II CPU use what socket?

AM2+ AM3

AMD FX CPU

AM3+ socket

what's wrong with this code? function () { return {key : "yo"}; }

ASI adds semicolon after return resulting in no return value.

Motherboard form factors

ATx, microATX, ITX, BTX

mutual pledge (spirit of the fraternity)

all for one and one for all

Windows Domain

Active Directory or like Linux's Samba, configure your linux systemt o use user accounts in the domain to authenticate to the local system.

Divisible by 3?

Add up all digits and see if divisble by 3. If so, the number is divisible by 3.

What is ceteris paribus?

All other things equal, all else unchanged, etc (think partial derivative)

First Greek letter fraternity for black women

Alpha Kappa Alpha, 1908, Howard university

ThirdWednesday of April

Alumni Day

ES6: Difference between function declarations and class declarations for OOP JS?

An important difference between function declarations and class declarations is that function declarations are hoisted and class declarations are not. You first need to declare your class and then access it, otherwise code like the following will throw a ReferenceError: var p = new Polygon(); // ReferenceError class Polygon {}

Object definition in OOP

An instance of a class.

What does it mean for an algorithm to converge?

An iterative algorithm is said to converge when as the iterations proceed the output gets closer and closer to a specific value. In some circumstances, an algorithm will diverge; its output will undergo larger and larger oscillations, never approaching a useful result. The "converge to a global optimum" phrase in your first sentence is a reference to algorithms which may converge, but not to the "optimal" value (e.g. a hill-climbing algorithm which, depending on initial conditions, may converge to a local maximum, never reaching the global maximum).

@angular/http

Angular's http client

Tomcat

Apache Tomcat is an open source software implementation of the Java Servlet and JavaServer Pages technologies. The Java Servlet and JavaServer Pages specifications are developed under the Java Community Process. Apache Tomcat is developed in an open and participatory environment and released under the Apache License version 2. Apache Tomcat is intended to be a collaboration of the best-of-breed developers from around the world. We invite you to participate in this open development project. To learn more about getting involved, click here. Apache Tomcat powers numerous large-scale, mission-critical web applications across a diverse range of industries and organizations. Some of these users and their stories are listed on the PoweredBy wiki page. Apache Tomcat, Tomcat, Apache, the Apache feather, and the Apache Tomcat project logo are trademarks of the Apache Software Foundation.

What is the root of an Angular 2 App?

AppComponent is the root of the application

Array.from()

Array instance from array-like object // Any iterable object... // Set var s = new Set(["foo", window]); Array.from(s); // ["foo", window] // Map var m = new Map([[1, 2], [2, 4], [4, 8]]); Array.from(m); // [[1, 2], [2, 4], [4, 8]] // String Array.from("foo"); // ["f", "o", "o"] // Using an arrow function as the map function to // manipulate the elements Array.from([1, 2, 3], x => x + x); // [2, 4, 6] Array.from() lets you create Arrays from: array-like objects (objects with a length property and indexed elements) or iterable objects (objects where you can get its elements, such as Map and Set). Array.from() has an optional parameter mapFn, which allows you to execute a map function on each element of the array (or subclass object) that is being created. More clearly, Array.from(obj, mapFn, thisArg) is the same as Array.from(obj).map(mapFn, thisArg), except that it does not create an intermediate array. This is especially important for certain array subclasses, like typed arrays, since the intermediate array would necessarily have values truncated to fit into the appropriate type. The length property of the from() method is 1.

Why is it unnecessary to change alpha over time to ensure that the gradient descent converges to a local minimum?

As we approach a local minimum, the gradient descent will take smaller steps because of the change of the derivative or the steepness of the cost function J. Don't need to worry about divergence.

Become genuinely interested in people - Knaphle

Asking for help to those who can help is a compliment to their skill and generates interest. "I have come to you for help because I can't think of anyone else who could be more capable of giving me the facts I want. I'm anxious to win this debate, and I'll deeply appreciate whatever help you can give me."

Remember names and use them - Franklin D Roosevelt, Napoleon III

Asking for names if they are unclear. "To recall a voter's name is statesmanship. To forget it is oblivion"

Properties of matrix multiplication?

Associative Trace Determinant: For square matrices only, the determinant of a product is the product of determinants:

What does AMD stand for?

Asynchronous module definition (AMD) is a JavaScript specification that defines an API for defining code modules and their dependencies, and loading them asynchronously if desired. Implementations of AMD provide the following benefits: Website performance improvements.

What does AMD stand for?

Asynchronous module definition designed with browser in mind

BSD

BSD is an os derived from UNIX at UC Berkeley.

Backslash next character interpreted literally (First know that this is a backslash, not a slash. Slashes go from L to R. A backslash that precedes a special character indicates that the next character is not special and should be interpreted literally. For example, the pattern /a*/ relies on the special character '*' to match 0 or more a's. By contrast, the pattern /a\*/ removes the specialness of the '*' to enable matches with strings like 'a*'.)

Function declarations vs Function Expressions - Best Practices?

Badly placed Function Declarations are misleading and there are few (if any) situations where you can't use a Function Expression assigned to a variable instead. However if you must use Function Declarations, it will minimize confusion if you place them at the top of the scope to which they belong. I would never place a Function Declarations in an if statement. Having said all this you may well find yourself in situations where it makes sense to use a Function Declaration. That's fine. Slavish adherance to rules is dangerous and often results in tortuous code. Much more important is that you understand the concepts so that you can make your own informed decisions. I hope this article helps in that regard.

AJS: Why is the <let> keyword stylistically good for <for> loops?

Because <let> indicates in the code that the variable being created is meant to only exist within that loop. For example, counters like (var i = 0; i < whatever; i++) indicates that, but does not functionally restrict access to i within that loop or block.

Explain hoisting in relation to the "Var" keyword

Because variable declarations (and declarations in general) are processed before any code is executed, declaring a variable anywhere in the code is equivalent to declaring it at the top. This also means that a variable can appear to be used before it's declared. This behavior is called "hoisting", as it appears that the variable declaration is moved to the top of the function or global code. bla = 2 var bla; // ... // is implicitly understood as: var bla; bla = 2;

NAGIOS Core

Bookmark and Share Nagios Core is the industry standard, Open Source IT monitoring system that enables organizations to identify and resolve IT infrastructure problems before they affect critical business processes. Nagios Core serves as one of the foundation blocks of Nagios XI - our commercial monitoring solution. Nagios Core allows you to monitor your entire IT infrastructure to ensure systems, applications, services, and business processes are functioning properly. In the event of a failure, it can alert technical staff of the problem, allowing them to begin remediation processes before outages affect business processes, end-users, or customers.

Primitive JS Datatypes

Boolean, Null, Undefined, Number, String, Symbol

SIGKILL (9)

Brute-force signal that kills process if process ws hung badly, will force sotp and may not clean after itself if this is used. better to use SIGTERM (15)

can any recursion function be turned into a function that uses iteration?

Can you always turn a recursive function into an iterative one? Yes, absolutely, and the Church-Turing thesis proves it if memory serves. In lay terms, it states that what is computable by recursive functions is computable by an iterative model (such as the Turing machine) and vice versa. The thesis does not tell you precisely how to do the conversion, but it does say that it's definitely possible. In many cases, converting a recursive function is easy. Knuth offers several techniques in "The Art of Computer Programming". And often, a thing computed recursively can be computed by a completely different approach in less time and space. The classic example of this is Fibonacci numbers or sequences thereof. You've surely met this problem in your degree plan.

AJS: What are the different ways to create a new scope?

Catch blocks, curly braces with <let> in ES6, functions.

[xyz]

Character set. (Character Sets - This pattern type matches any one of the characters in the brackets, including escape sequences. Special characters like the dot(.) and asterisk (*) are not special inside a character set, so they don't need to be escaped. You can specify a range of characters by using a hyphen, as the following examples illustrate. The pattern [a-d], which performs the same match as [abcd], matches the 'b' in "brisket" and the 'c' in "city". The patterns /[a-z.]+/ and /[\w.]+/ match the entire string "test.i.ng".)

Classifier?

Classifier: A classifier is a special case of a hypothesis (nowadays, often learned by a machine learning algorithm). A classifier is a hypothesis or discrete-valued function that is used to assign (categorical) class labels to particular data points. In the email classification example, this classifier could be a hypothesis for labeling emails as spam or non-spam. However, a hypothesis must not necessarily be synonymous to a classifier. In a different application, our hypothesis could be a function for mapping study time and educational backgrounds of students to their future SAT scores.

console.clear()

Clears the console.

var pet = function(name) { // The outer function defines a variable called "name" var getName = function() { return name; // The inner function has access to the "name" variable of the outer function } return getName; // Return the inner function, thereby exposing it to outer scopes }, myPet = pet("Vivie"); myPet(); // Returns "Vivie"

Closure

CUPS

Common Uni Printing System -- allows printing across linux server uses IPP on port 631

Browserify allows you to use CommonJS or AMD or RequireJS?

CommonJS in the browser! Remember RequireJS implements the AMD api.

Does Node implement CommonJS or AMD?

CommonJS. RequireJS IMPLEMENTS the AMD api

@angular/router

Component router.

$ (Anchor)

Match end of input ( If the multiline flag is set to true, also matches immediately before a line break character. For example, /t$/ does not match the 't' in "eater", but does match it in "eat".)

Network

Enables the routing of the data. It specified how to recognize the address of neighboring nodes and routers. It also specifies how to determine the next netowrk point to which a packet should be forwarded toward its destination. The Internet Protocol (IP) operates at this layer, as does the Internet Control Message Protocol (ICMP)

+ (Quantifier)

Match preceding expression 1 or more (For example, /a+/ matches the 'a' in "candy" and all the a's in "caaaaaaandy", but nothing in "cndy".)

Match single non white-space character

Linux Process loading

all linux processes are directly or indirectly loaded by INIT process

Match non-digit character (Matches any character that is not a digit in the basic Latin alphabet. Equivalent to [^0-9]. For example, /\D/ or /[^0-9]/ matches "B" in "B2 is the suite number".)

Smile - Takeways

Give positive feedback, let people know that you're listening. Smile, laugh out loud. The expression one wears on one's face is far more important than the clothes on wears on one's back.

Derive SSE

Given a linear regression model, the difference at each predicted point with the correct point is given by diff = y_i - (mx + b)

When code is executed, an execution context is created. What is created within this execution context ALWAYS?

Global object, <this>

Go To command (prefix with number - 5G goes to line 5)

Object.assign

Creates a new object by copying the values of all enumerable own properties from one or more source objects to a target object. Object.create(proto[, propertiesObject])

What is cross-validation?

Cross-validation, sometimes called rotation estimation,[1][2][3] is a model validation technique for assessing how the results of a statistical analysis will generalize to an independent data set. It is mainly used in settings where the goal is prediction, and one wants to estimate how accurately a predictive model will perform in practice. In a prediction problem, a model is usually given a dataset of known data on which training is run (training dataset), and a dataset of unknown data (or first seen data) against which the model is tested (testing dataset).[4] The goal of cross validation is to define a dataset to "test" the model in the training phase (i.e., the validation dataset), in order to limit problems like overfitting, give an insight on how the model will generalize to an independent dataset (i.e., an unknown dataset, for instance from a real problem), etc.

Three principle quotes

Cultivation of friendship among its members; acquirement individually of a high degree of mental culture, attainment personally of a high standard of morality

SOLI*D*

DIP - Dependency Inversion Principle (In object-oriented programming, the dependency inversion principle refers to a specific form of decoupling software modules. When following this principle, the conventional dependency relationships established from high-level, policy-setting modules to low-level, dependency modules are reversed, thus rendering high-level modules independent of the low-level module implementation details. The principle states:[1] A. High-level modules should not depend on low-level modules. Both should depend on abstractions. B. Abstractions should not depend on details. Details should depend on abstractions.)

CMD + O

Go to class

Historic Meetings

Dec 26 - create a secret society, 28 - report of committee was considered and amended, 30 - report was further debated and finally adopted, January 1st - first pledge.

Class definition

Defines the object's characteristics. A class is a template definition of an object's properties and methods.

GNOME

Desktop environment for Linux

DMAC - System Resource

Direct Memory Access Channels - used by high-throughput devices to communicate directly with RAM without involving CPU. Bypassing CPU can dramatically increase device's data transfer rate. No two devices can use the same channel.

Nobody complains when you mop the floor.

Do work that is undesired. Don't ask. It's an asset.

Male graduate term

almnus

If you want to gather honey, don't kick over the beehive

Don't criticize, condemn, or complain.

Sipping beverages

Don't sip until mouth is empty and has been wiped with a napkin. Keeps rim of cup or glass free from food marks

What does don't block the event loop mean?

Dont put slow blocking code onto the stack. the event loop wont put other functions onto the stack until it is clear!

Minix

Dr. Andrew S. Tanenbaum's clone of the commercial UNIX OS.

What is the counterpart to lexical scoping?

Dynamic scoping

Why use one line functions?

Don't be scared of 1-line functions! A lot of programmers seem to have a mental block about 1-line functions, you shouldn't. If it makes the code clearer and cleaner, extract the line into a function. Performance probably won't be affected. Any decent compiler made in the last decade (and perhaps further) will automatically inline a simple 1-line function. Also, 1-line of C can easily correspond to many lines of machine code. You shouldn't assume that even in the theoretical case where you incur the full overhead of a function call that this overhead is significant compared to your "one little line". Let alone significant to the overall performance of your application. Abstraction Leads to Better Design. (Even for single lines of code) Functions are the primary building blocks of abstract, componentized code, they should not be neglected. If encapsulating a single line of code behind a function call makes the code more readable, do it. Even in the case where the function is called once. If you find it important to comment one particular line of code, that's a good code smell that it might be helpful to move the code into a well-named function. Sure, that code may be 1-line today, but how many different ways of performing the same function are there? Encapsulating code inside a function can make it easier to see all the design options available to you. Maybe your 1-line of code expands into a call to a webservice, maybe it becomes a database query, maybe it becomes configurable (using the strategy pattern, for example), maybe you want to switch to caching the value computed by your 1-line. All of these options are easier to implement and more readily thought of when you've extracted your 1-line of code into its own function. Maybe Your 1-Line Should Be More Lines. If you have a big block of code it can be tempting to cram a lot of functionality onto a single line, just to save on screen real estate. When you migrate this code to a function, you reduce these pressures, which might make you more inclined to expand your complex 1-liner into more straightforward code taking up several lines (which would likely improve its readability and maintainability).

ES6 arrow and this note

ECMAScript 2015 introduced arrow functions whose this is lexically scoped (it is set to the this value of the enclosing execution context)

Files and modules in Node are in one to one correspondence. What does this mean?

Each js file is its own module. //foo.js const circle = require('./circle.js'); console.log( `The area of a circle of radius 4 is ${circle.area(4)}`); //circle.js const PI = Math.PI; exports.area = (r) => PI * r * r; exports.circumference = (r) => 2 * PI * r;

How do they differ from each other?

Each method differs in how this is initialized.

"Batch" Gradient Descent (BGD or GD)

Each step of gradient descent uses all the training examples. batch GD - This is different from (SGD - stochastic gradient descent or MB-GD - mini batch gradient descent) In GD optimization, we compute the cost gradient based on the complete training set; hence, we sometimes also call it batch GD. In case of very large datasets, using GD can be quite costly since we are only taking a single step for one pass over the training set -- thus, the larger the training set, the slower our algorithm updates the weights and the longer it may take until it converges to the global cost minimum (note that the SSE cost function is convex).

General Convetion powers and responsibilities

Electing the General council, Revoking charters of chapters, Providing for the raising and disbursement of revenues, enacting laws for the regulation of the fraternity.

How to set an attribute on an element in Pure JS DOM?

Element.setAttribute() -- element.setAttribute(name, value); *name* is the name of the attribute as a string. *value* is the desired new value of the attribute.

What is the downside of using an alpha (learning rate) that is too small?

Gradient descent can be way too slow.

What are the three configurable or not so configurable Object properties?

Enumerable: I can access to all of them using a for..in loop. Also, enumerable property keys of an object are returned using Object.keys method. Writable: I can modify their values, I can update a property just assigning a new value to it: ob.a = 1000; Configurable: I can modify the behavior of the property, so I can make them non-enumerable, non-writable or even non-cofigurable if I feel like doing so. Configurable properties are the only ones that can be removed using the delete operator.

What is an error-first callback?

Error-first callbacks are used to pass errors and data. The first argument is always an error object that the programmer has to check if something went wrong. Additional arguments are used to pass data. (fs.readFile(filePath, function(err, data) { if (err) { //handle the error } // use the data object });)

Convention of 1920

Established a central office and created position of exec. secretary to have charge of it.

Fourth and fifth editions

Executive Secretary, Arthur R. Priest, Depauw 1891

What is feature scaling?

Feature scaling is a method used to standardize the range of independent variables or features of data. In data processing, it is also known as data normalization and is generally performed during the data preprocessing step. The range of values of raw data varies widely, in some machine learning algorithms, objective functions will not work properly without normalization[citation needed]. For example, the majority of classifiers calculate the distance between two points by the Euclidean distance[citation needed]. If one of the features has a broad range of values, the distance will be governed by this particular feature[citation needed]. Therefore, the range of all features should be normalized so that each feature contributes approximately proportionately to the final distance[citation needed]. Another reason why feature scaling is applied is that gradient descent converges much faster with feature scaling than without it[citation needed]. Some methods are rescaling, standardization, scaling to unit length.

Synonym for Input variable?

Features

What are the three package categories in the dependencies section of package.json?

Features - Feature packages provide our application with framework and utility capabilities. Polyfills - Polyfills plug gaps in the browser's JavaScript implementation. Other - Other libraries that support the application such as bootstrap for HTML widgets and styling.

What is the initiator column on Network tab?

File and line that requested resource

Why do we square instead of using the absolute value when calculating variance and standard deviation?

First I'll answer the mathematical question asked in the question details, which I'm going to restate because I think it is stated wrong: The short answer is "Because of Jensen's inequality." See http://en.wikipedia.org/wiki/Jen... and the rest of the article for context. It says in particular that for a concave function What about the more general question, "Why variance?" I don't believe there is any compelling conceptual reason to use variance as a measure of spread. If forced to choose, my guess is that most people would say more robust measures like interquartile range or MAD better capture the concept of "spread" in most cases. But variance (and more generally "sum of squares") has some attractive properties, many of which flow from the Pythagorean theorem one way or another. Here some of them, without much math: We can decompose sums of squares into meaningful components like "between group variance" and "within-group variance." To generalize the above point, when a random variable Y Y is partly explained by another random variable X X there is a useful decomposition of the variance of Y Y into the part explained by X X and the unexplained part. (See http://en.wikipedia.org/wiki/Law...). If we think more broadly about mean squared error, this too can be decomposed into the sum of variance and squared bias. It is easy to interpret this total error as the sum of "systematic error" and "noise." Often we want to minimize our error. When the error is a sum of squares, we are minimizing something quadratic. This is easily accomplished by solving linear equations. So yes, variance and mean squared error are conveniences rather than conceptual necessities. But they are convenient conveniences.

Secret society literary and social in nature but not Greek

Flat hat club

JQUERY: event.which

For key or mouse events, this property indicates the specific key or button that was pressed.

FSF - Free Software Foundation

Free Software Foundation - Richard Stallman - Free is ability rto copy and reuse software -- launched GNU Project and GPL

What is the downside of using an alpha (learning rate) that is too big?

Gradient descent can overshoot the minimum and it may fail to converge or even diverge.

Apache OpenOffice

Full productivity suite

Backup Types

Full, Incremental, Differntial

What letter is typically used to depict a cost function?

Function J

Var has what scope?

Function scope

Lexical Scope Definition

Functions in JavaScript are lexically rather than dynamically scoped. This means that they run in the scope in which they are defined, not the scope from which they are executed. Prior to JavaScript 1.2, functions could be defined only in the global scope, and lexical scoping was not much of an issue: all functions were executed in the same global scope (with the call object of the function chained to that global scope).

GFI LANGUARD

GFI LANguard : A commercial network security scanner for Windows - See more at: http://blog.kaffenews.com/2010/02/02/top-10-vulnerability-scanners/#sthash.hG9l115L.dpuf

GPL

GNU General Public License - requires source code remain freely available to anyone who wants it.

Two members of PDT that have been honored by sororities

George Banta Sr., Franklin-Indiana 1876, Guy Potter Bento, Ohio Wesleyan 1886

First president of GeneralCouncil

George Banta, Franklin-Indiana 1876

Become genuinely interested in people - Howard Thurston

Greatest magician who told himself, "I am grateful because these people come to see me. They make it possible for me to make my living in a very agreeable way. I'm going to five them the very best I possibly can. "I love my audience." before every show.

Robert MOrrison was an exceptional scholar in..

Greek and Latin

SYSLOGD

HANDLES LOGGING ON A LINUX SYSTEM

Web Event: DOMContentLoaded

HTML document loaded (The DOMContentLoaded event is fired when the initial HTML document has been completely loaded and parsed, without waiting for stylesheets, images, and subframes to finish loading. https://developer.mozilla.org/en-US/docs/Web/Events/DOMContentLoaded)

port 80

HTTP

Port 443

HTTPS

ifconfig parameters

HW addr, inet addr, Bcast, Mask, RX packets, TX packets, Collisions, RX bytes, TX bytes

What is a nibble in Computer Programming?

Half an octet, 4-bit aggregation 0xF

Types of Link Files

Hard and Symbolic links -- symbolic points to another file in file system. but a symoblic link has its own inode Hard link file points directly to the inode of another file. no pointer and pointee

What are polymorphic types in Haskell?

Haskell also incorporates polymorphic types---types that are universally quantified in some way over all types. Polymorphic type expressions essentially describe families of types. For example, (forall a)[a] is the family of types consisting of, for every type a, the type of lists of a. Lists of integers (e.g. [1,2,3]), lists of characters (['a','b','c']), even lists of lists of integers, etc., are all members of this family. (Note, however, that [2,'b'] is not a valid example, since there is no single type that contains both 2 and 'b'.)

HDD

Heads, Cylinders, Sectors per track,

Why is writing code for Node different?

Highly dependent on using callbacks to take full advantage of asynchronous (non-blocking) pattern and event loops.

Smile - Perception

How do people perceive work? Perception is everything. It isnt what you have or who you are or where you are or what you are doing that makes you happy or unhappy. It is what you think about it.

Oath

I now declare that I pledge myself and my services to the Phi Delta Theta Fraternity. That I will discharge faithfully the duties devolving upon me as a Phikeia, and that I will try to promote the welfare of the Fraternity, and that I will be always mindful of the basic principles of the Fraternity. And further, I pledge myself as a college man to uphold the honor and dignity of Phi Delta Theta, everywhere and at all times. I will never bring disgrace to this, my Fraternity, by any act of dishonesty or moral cowardice. I will stand firm for the ideals and sacred things of my Fraternity, both alone and with my Phikeia Brothers. I will revere and obey the laws of the Fraternity, and do my best to incite a like respect and reverence in my Phikeia brothers and in every member of this chapter. I will strive in all ways to transmit the Fraternity to thoswe who may follow after, not only not less, but greater than it was transmitted to me.

DenyHosts

IPTables alternative

Verify your backups

If theres too much system load while backing up you may end up with errors in your backups. It's important to verify your backups.

postfix vs prefix operators

If used postfix, with operator after operand (for example, x++), then it returns the value before incrementing. If used prefix with operator before operand (for example, ++x), then it returns the value after incrementing. // Postfix var x = 3; y = x++; // y = 3, x = 4 // Prefix var a = 2; b = ++a; // a = 3, b = 3

The Biggest Gotcha with JavaScript "this" keyword

If you understand this one principle of JavaScript's this, you will understand the "this" keyword with clarity: this is not assigned a value until an object invokes the function where this is defined. Let's call the function where this is defined the "this Function." Even though it appears this refers to the object where it is defined, it is not until an object invokes the this Function that this is actually assigned a value. And the value it is assigned is based exclusively on the object that invokes the this Function. this has the value of the invoking object in most circumstances. However, there are a few scenarios where this does not have the value of the invoking object. I touch on those scenarios later.

Gradient Descent algorithm

Image result for gradient descent Gradient descent is a first-order optimization algorithm. To find a local minimum of a function using gradient descent, one takes steps proportional to the negative of the gradient (or of the approximate gradient) of the function at the current point. used with simultaneous updates of the parameters of success Susceptible to falling into local optimum depending on initialization.

the In "non-strict" mode if the value of the first argument is null or undefined, What is value of the first argument replaced with?

In "non-strict" mode, if the value of the first argument is null or undefined, it is replaced with the global object.

* (Quantifier)

Match preceding expression 0 or more times (For example, /bo*/ matches 'boooo' in "A ghost booooed" and 'b' in "A bird warbled", but nothing in "A goat grunted".)

In Javascript what are namespaces?

In JavaScript a namespace is just another object containing methods, properties, and objects. (The idea behind creating a namespace in JavaScript is simple: create one global object, and all variables, methods, and functions become properties of that object. Use of namespaces also reduces the chance of name conflicts in an application, since each application's objects are properties of an application-defined global object. )

K-Fold?

In k-fold cross-validation, the original sample is randomly partitioned into k equal sized subsamples. Of the k subsamples, a single subsample is retained as the validation data for testing the model, and the remaining k − 1 subsamples are used as training data. The cross-validation process is then repeated k times (the folds), with each of the k subsamples used exactly once as the validation data. The k results from the folds can then be averaged to produce a single estimation. The advantage of this method over repeated random sub-sampling (see below) is that all observations are used for both training and validation, and each observation is used for validation exactly once. 10-fold cross-validation is commonly used,[7] but in general k remains an unfixed parameter. When k=n (the number of observations), the k-fold cross-validation is exactly the leave-one-out cross-validation. In stratified k-fold cross-validation, the folds are selected so that the mean response value is approximately equal in all the folds. In the case of a dichotomous classification, this means that each fold contains roughly the same proportions of the two types of class labels. Ultimately this helps fix the problem that we want to maximize both the training and test sets in cross-validation.

What is lazy evaluation?

In programming language theory, lazy evaluation, or call-by-need[1] is an evaluation strategy which delays the evaluation of an expression until its value is needed (non-strict evaluation) and which also avoids repeated evaluations (sharing).[2][3] The sharing can reduce the running time of certain functions by an exponential factor over other non-strict evaluation strategies, such as call-by-name.[citation needed] The benefits of lazy evaluation include: The ability to define control flow (structures) as abstractions instead of primitives. The ability to define potentially infinite data structures. This allows for more straightforward implementation of some algorithms. Performance increases by avoiding needless calculations, and error conditions in evaluating compound expressions.

Encapsulation definition

In programming languages, encapsulation is used to refer to one of two related but distinct notions, and sometimes to the combination[1][2] thereof: A language mechanism for restricting direct access to some of the object's components.[3][4] A language construct that facilitates the bundling of data with the methods (or other functions) operating on that data.[5][6] Some programming language researchers and academics use the first meaning alone or in combination with the second as a distinguishing feature of object-oriented programming, while other programming languages which provide lexical closures view encapsulation as a feature of the language orthogonal to object orientation. The second definition is motivated by the fact that in many OOP languages hiding of components is not automatic or can be overridden; thus, information hiding is defined as a separate notion by those who prefer the second definition. The features of encapsulation are supported using classes in most object-oriented programming languages, although other alternatives also exist.

What is a simple linear regression?

In statistics, simple linear regression is the least squares estimator of a linear regression model with a single explanatory variable. In other words, simple linear regression fits a straight line through the set of n points in such a way that makes the sum of squared residuals of the model (that is, vertical distances between the points of the data set and the fitted line) as small as possible. minimize squared error

Inflection points

Inflection points are where the function changes concavity. Since concave up corresponds to a positive second derivative and concave down corresponds to a negative second derivative, then when the function changes from concave up to concave down (or vise versa) the second derivative must equal zero at that point. So the second derivative must equal zero to be an inflection point. But don't get excited yet. You have to make sure that the concavity actually changes at that point.

Inside object literals, what does the <this> keyword refer to?

Inside Object literals, the this value will always refer to it's own Object. Nice and simple to remember. / create an object var myObject = {}; // create a method on our object myObject.someMethod = function () { console.log(this); }; // call our method myObject.someMethod();

IRQ - System Resource

Interrupt Request Channel, every device in PC assigned an interrupt, multiple PCI devices can share interrupts but devices that use olderexpansion buses cannot. -- allows to call the CPU, calls CPU for attention as communication between hardware and software.

ES6: Why the hell are there classes in ES6?

JavaScript classes are introduced in ECMAScript 6 and are syntactical sugar over JavaScript's existing prototype-based inheritance. The class syntax is not introducing a new object-oriented inheritance model to JavaScript. JavaScript classes provide a much simpler and clearer syntax to create objects and deal with inheritance.

What do objects have in js?

JavaScript functions have properties and methods.

How does JS define classes?

JavaScript uses functions as constructors for classes. Defining a class is as easy as defining a function. In the example below we define a new class called Person with an empty constructor. var Person = function () {};

In JS how is short circuiting different?

Javacript uses short-circuit evaluation for logical operators || and &&. However, it's different to other languages in that it returns the result of the last value that halted the execution, instead of a true, or false value.

Authors of Bond of PDT

John MOrriosn Miami Ohio 1849, John McMillan Wilson, Miami-Ohio 1849

Which caches are in each core?

L1, L2

Which cache is shared among entire CPU?

Intel Core i3/i5/i7 use what socket?

LGA 1155

STACK ACRONYM

LIFO - push, pop, size, peek or top (push returns size of stack, but pushes an element onto stack, pop - pops off top and returns that value, size() returns value of size)

SO*L*ID

LSP - Liskov Substitution Principle Derived classes must be substitutable by their base classes.

Learning algorithm?

Learning algorithm: Again, our goal is to find or approximate the target function, and the learning algorithm is a set of instructions that tries to model the target function using our training dataset. A learning algorithm comes with a hypothesis space, the set of possible hypotheses it can come up with in order to model the unknown target function by formulating the final hypothesis

Higher derivatives?

Let f be a differentiable function, and let f ′(x) be its derivative. The derivative of f ′(x) (if it has one) is written f ′′(x) and is called the second derivative of f. Similarly, the derivative of a second derivative, if it exists, is written f ′′′(x) and is called the third derivative of f. Continuing this process, one can define, if it exists, the nth derivative as the derivative of the (n-1)th derivative. These repeated derivatives are called higher-order derivatives. The nth derivative is also called the derivative of order n.

Lexical Scoping?

Lexical Scoping defines how variable names are resolved in nested functions: inner functions contain the scope of parent functions even if the parent function has returned.

What is a synonym for static scope?

Lexical scope

AJS: What is lexical scope? (Kyle Simpson)

Lexical scope is scope that is defined at lexing time. In other words, lexical scope is based on where variables and blocks of scope are authored, by you, at write time, and thus is mostly set in stone by the time the lexer processes the code.

AJS: What scope does JS have as specifically as possible?

Lexical scoping with function scope.

Native vs Library Methods - when to use?

Library methods should be used for contrived and convoluted uses of native methods that often confuse more than make progress in code. However, if there is a native method for a specific task that is tailored to that task always use the native method.

System V init scripts

Linux distros that use System V init scripts store them in the /etc/rc.d directory within this /etc/rc.d are a series of subd's named rc0.d thru rc6.d -- each of these directories is associated with a particular runlevel.

Concurrent Running

Linux switches between various processes on CPU making it appear as if its working on concurrent processes

? (Quantifier)

Make preceding token optional. (The question mark makes the preceding token in the regular expression optional. colou?r matches both colour and color. The question mark is called a quantifier. You can make several tokens optional by grouping them together using parentheses, and placing the question mark after the closing parenthesis. E.g.: Nov(ember)? matches Nov and November. You can write a regular expression that matches many alternatives by including more than one question mark. Feb(ruary)? 23(rd)? matches February 23rd, February 23, Feb 23rd and Feb 23. For example, /e?le?/ matches the 'el' in "angel" and the 'le' in "angle" and also the 'l' in "oslo".)

Haskell: What do back quotes do for operators?

Makes the operator infix

Map mneumonic

Map maps a function onto each value on an array.

Founder's day

March 16 in 1910

PATA

Master/slave hard drive

{N}

Match N of preceding expression (Bounded repeat: Matches exactly n occurrences of the preceding expression. N must be a positive integer. For example, /a{2}/ doesn't match the 'a' in "candy," but it does match all of the a's in "caandy," and the first two a's in "caaandy.")

Match white space character. (Matches a single white space character, including space, tab, form feed, line feed. Equivalent to [ \f\n\r\t\v\u00a0\u1680\u180e\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff]. For example, /\s\w*/ matches ' bar' in "foo bar.")

\B meaning

Matches a non-word boundary. This matches a position where the previous and next character are of the same type: Either both must be words, or both must be non-words. The beginning and end of a string are considered non-words.

\b meaning

Matches a word boundary. A word boundary matches the position where a word character is not followed or preceeded by another word-character. Note that a matched word boundary is not included in the match. In other words, the length of a matched word boundary is zero. (Not to be confused with [\b].)

(x)

Matches x and remembers the match (called capturing groups)

Ctrl+B (⌘B) or Ctrl+Click (⌘-Click)

Navigate to declaration: Ctrl+B (⌘B) or Ctrl+Click (⌘-Click) You can instantly jump to the function or method definition or a variable, class, component, or CSS style declaration: just Ctrl-click on it, or place the caret on it and press Ctrl+B. This shortcut can also help you jump to the referenced file or imported module:

Why add methods using prototype as opposed to using this?

Methods that inherit via the prototype chain can be changed universally for all instances, for example: function Class () {} Class.prototype.calc = function (a, b) { return a + b; } // Create 2 instances: var ins1 = new Class(), ins2 = new Class(); // Test the calc method: console.log(ins1.calc(1,1), ins2.calc(1,1)); // -> 2, 2 // Change the prototype method Class.prototype.calc = function () { var args = Array.prototype.slice.apply(arguments), res = 0, c; while (c = args.shift()) res += c; return res; } // Test the calc method: console.log(ins1.calc(1,1,1), ins2.calc(1,1,1)); // -> 3, 3 ) Notice how changing the method applied to both instances? This is because ins1 and ins2 share the same calc() function. In order to do this with public methods created during construction, you'd have to assign the new method to each instance that has been created, which is an awkward task. This is because ins1 and ins2 would have their own, individually created calc() functions. Another side effect of creating methods inside the constructor is poorer performance. Each method has to be created every time the constructor function runs. Methods on the prototype chain are created once and then "inherited" by each instance. On the flip side of the coin, public methods have access to "private" variables, which isn't possible with inherited methods. var YourClass = function(){ var privateField = "somevalue"; this.publicField = "somevalue"; this.instanceMethod1 = function(){ //you may access both private and public field from here: //in order to access public field, you must use "this": alert(privateField + "; " + this.publicField); }; } YourClass.prototype.instanceMethod2 = function(){ //you may access only public field 2 from this method, but not private fields: alert(this.publicField); //error: drawaback of prototype methods: alert(privateField); }; When you define methods via prototype, they are shared among all YourClass instances. As a result the total size of such instances is less than if you define methods in constructor; There are tests that show how method definition via prototype decrease the total size of html page and as a result a speed of its loading. another advantage of methods, defined via prototype - is when you use inherited classes, you may override such methods and in the overriden method of the derived class you may invoke the method of base class with the same name, but with methods defined in constructor, you cannot do this.

Base

Microsoft Access - Database - Linux

Epiphany

Minimalistic browser that provides basic Web browsing functionality

ModSecurity

ModSecurity is an open source, cross-platform web application firewall (WAF) module. Known as the "Swiss Army Knife" of WAFs, it enables web application defenders to gain visibility into HTTP(S) traffic and provides a power rules language and API to implement advanced protections.

Model definition?

Model: In machine learning field, the terms hypothesis and model are often used interchangeably. In other sciences, they can have different meanings, i.e., the hypothesis would be the "educated guess" by the scientist, and the model would be the manifestation of this guess that can be used to test the hypothesis.

Formal introductions

Mr. Guest, may I present Mr.Member . Introduce a gentleman to a lady, a member toa guest, anda young person to a markedly older person. Distinguished people are to be introduced to. i.e. Dr.Taylor, let me present Miss Patterson

Bazaar Model

Much less organized than cathedral model. relies on extensive collaboration

Alt+Click

Multiple Cursor or Multiline edit

Matrix scalar multiplication rules?

Multiply the scalar against each number in the matrix.

Port 119

NNTP (news)

Array.prototype.concat - does it mutate the given array?

Nah, creates a new one. See specs: http://www.ecma-international.org/ecma-262/5.1/#sec-15.4.4.4

Haskell: do strings exist in Haskell?

Nah, lists of chars do though [Char] single chars can be written with single quotes while list of chars can be written with double quotes

Plug-n-play - system resource

Needs BIOS, device , OS

NESSUS

Nessus. $1,500/yr; Nessus® is the industry's most widely-deployed vulnerability, configuration, and compliance scanner. For Individuals; Scan Unlimited IPs ...

NIS

Network Information Service -- designed to provide centralized user account management when you have multiple systms that all need the same user accounts

Do arrow functions with one param require parens?

Does Array.prototype.filter mutate the given array?

Does Array.prototype.map mutate the given array?

Does Array.prototype.reduce mutate the given array?

A minor

No Flats

Does Javascript have function overloading?

No, you cannot double-define functions in the same scope.

What are special characters in regular expressions?

Non-direct match search (When the search for a match requires something more than a direct match, such as finding one or more b's, or finding white space, the pattern includes special characters. For example, the pattern /ab(asterisk)c/ matches any character combination in which a single 'a' is followed by zero or more 'b's (* means 0 or more occurrences of the preceding item) and then immediately followed by 'c'. In the string "cbbabbbbcdebc," the pattern matches the substring 'abbbbc'.)

Standardization vs normalization

Normalization rescales the values from to a range of [0,1]. This might useful in some cases where all parameters need to have the same positive scale, but outliers from data set are lost. Xchanged = (X - Xmin)/(Xmax-Xmin) Standardization rescales data to have a mean of 0 and standard deviation of 1 (unit variance). Xchanged = (x-mean)/sd For most applications standardization is recommended. In the business world, "normalization" typically means that the range of values are "normalized to be from 0.0 to 1.0". "Standardization" typically means that the range of values are "standardized" to measure how many standard deviations the value is from its mean. However, not everyone would agree with that. It's best to explain your definitions before you use them. In any case, your transformation needs to provide something useful.

is "this" a variable? can its value be changed?

Note that this is not a variable. It is a keyword. You cannot change the value of this.

What does <this> hold in global functions and anonymous functions that are not bound to any object in strict mode?

Note that when we use strict mode, this holds the value of undefined in global functions and in anonymous functions that are not bound to any object.

Zenoss

OS (open source) IT management application that allows monitoring of network

OSSEC

OSSEC is an Open Source Host-based Intrusion Detection System that performs log analysis, file integrity checking, policy monitoring, rootkit detection, real-time alerting and active response.

new vs Object.create for instantiating objects of classes?

Object.create

Array, Date, Function are all what datatype?

Objects

Nonprimitive JS Datatype

Objects

Bitwise Swap Intuition x = x xor y y = x xor y x = x xor y

On line 1 we combine x and y (using XOR) to get this "hybrid" and we store it back in x. XOR is a great way to save information, because you can remove it by doing an XOR again. So, this is exactly what we do on line 2. We XOR the hybrid with y, which cancels out all the y information, leaving us only with x. We save this result back into y, so now they have swapped. On the last line, x still has the hybrid value. We XOR it yet again with y (now with x's original value) to remove all traces of x out of the hybrid. This leaves us with y, and the swap is complete! *The mathematics are fairly simple and work because XOR has a useful property, when you XOR A and B, you get a value C. If you XOR C and A you'll get B back, if you XOR C and B you'll get A back.*

Transport Layer

On the sending host the Transprt ayer receives information from the upper alyers of the OSI model and divides it into small transmittable chunks called packets. on receiving host the transport layer reassembles packets form datagrams received from lower layers of OSI model. the transport layer provides error-checking mechans to ensure that dat arrives at destination host intact. TCP and UDP operate at this layer

What is the essential structure of an ng2 Component?

One or more import statements to reference the things we need. A @Component decorator that tells Angular what template to use and how to create the component. A component class that controls the appearance and behavior of a view through its template.

Incremental Backup

Only the files that have been modified since the last backup (full or incremental) are backed up. Ecah file is flagged as having been backed up.

Differential Backup

Only the files that have been modified since the last full backup are backed up. Even though they have been backed up during a differentialb ackup, the files invovled are not flagged as having been backed up

:sp filename

Open a file in a new buffer and split window

inspect(object/function)

Open element in appropriate panel. (inspect(object/function) opens and selects the specified element or object in the appropriate panel: either the Elements panel for DOM elements or the Profiles panel for JavaScript heap objects.)

$(object/function)

Open in inspect ?

Blender

Open source 3d rendering

Calibre

Open source e-book amangement

AMD CPUs

Opteron, Phenom FX, Phenom X4, Phenom X3, Athlon 6-series, Athlon 4-series, Athlon X2, Sempron

Lines of AMD CPU

Opteron, Phenom, Athlon, Sempron

BSD init scripts

Other linux distros use BSD init scripts -- these reside in the /etc/init.d directory

Router

Our server will need to answer differently to requests, depending on which URL the request was asking for, thus we need some kind of router in order to map requests to request handlers

Silverware order

Outside in. Utensils used for first course are farthest and closer as courses progress.

syntax for redefining variables

PATH= $PATH: /var/opt/myapp -- adding a new path location

Expansion Buses

PCI, AGP, PCIe, AMR, CNR, PCMCIA

Impress

PPT Linux

Pause on exceptions

Pause button on right (While it's paused you can hover over variables to see its values!)

Pause on uncaught exceptions

Pause button on right twice or in settings.

Intel CPUs

Pentium 4, Core 2, Pentium Dual Core, Celeron, Celeron M, Core i3 (1st and 2nd Generation) Core i5 (1st and 2nd Generation) Core i7 (1st and 2nd generation) Xeon (1st and 2nd generation)

Lines of Intel CPU

Pentium Celeron, Core iX, Xeon

Smile - Fun and Success

People rarely succeed at anything unless they have fun at it.

First Greek Letter Organization...

Phi Beta Kappa 1776, College of WIlliam and Mary

Walter B Palmer, emory-Vanderbilt 1877

Phi Delta Theta was organized with tthree principle objectives: The cultivation of friendship among its members; the acquirement individually of a high degree of mental culture, and the attainment personally of a high standard of morality

OSI Layers

Physical, Data Link, Network, Transport, Session, Presentation, Application

First organization of college women established as a national college fraternity

Pi Beta Phi 1867

Object.prototype.__proto__

Points to the object which was used as prototype when the object was instantiated.

Polymorphism defintiion

Poly means "many" and morphism means "forms". Different classes might define the same method or property.

Ports

Ports are provided by bothtthe TCP and UDP protocols at the Transport layer. In essecnce, a port is a logical connection provided by TCP and UDP for upper-layer protocols. Ports allow a single host wiht a single IP address assigned to provide multiple network services. Each service uses hte same IP address but operates using a different TCP or UDP port number.

General Council roles

President, Secretary, treasureser, historian, (reporter) later came in

Remember names and use them - Andrew Carnegie

Pullman donation by simple renaming of factories of steel manufacturers

CPU Speed - CLock Speed

Pulses set tempo for CPU and are measured in MHz, or minillion pulses per second.

pandas.DataFrame.loc

Purely label-location based indexer for selection by label. .loc[] is primarily label based, but may also be used with a boolean array. Allowed inputs are: A single label, e.g. 5 or 'a', (note that 5 is interpreted as a label of the index, and never as an integer position along the index). A list or array of labels, e.g. ['a', 'b', 'c']. A slice object with labels, e.g. 'a':'f' (note that contrary to usual python slices, both the start and the stop are included!). A boolean array. A callable function with one argument (the calling Series, DataFrame or Panel) and that returns valid output for indexing (one of the above) .loc will raise a KeyError when the items are not found.

Regression vs Classification?

Regression: the output variable takes continuous values. - Price of house given a size. Classification: the output variable takes class labels, or discrete value output - Breast cancer, malignant or benign? Almost like quantitative vs categorical

The callback pattern for async code is more... The event pattern for async code is more...

Request/Reply -- no results until all results -- Publish/Subscribe -- act on results as they come in -- so the .on is kind of like a subscription when an event occurs.

Object.prototype.hasOwnProperty()

Returns a boolean indicating whether an object contains the specified property as a direct property of that object and not inherited through the prototype chain.

Object.prototype.isPrototypeOf()

Returns a boolean indication whether the specified object is in the prototype chain of the object this method is called upon.

Save to local after modifying Sources to see the effect?

Right click + save

Who wrote the preface?

Robert A Biggs, Georgia Southern `76

Who wrote the preface?

Robert A Biggs, Georgia Southern `76.

Immortal Six

Robert Morrison, Miami-Ohio 1849. John McMillan Wilson, Miami-Ohio 1849, Robert Thompson Drake Miami Ohio 1850, John Wolfe Lindley Miami Ohio 1850, Adrivan walker Rodgers, Miami Ohio 1851 Andrew Watts Rogers, Miami Ohio 1851

Phikeia meeting procedure

Roll Call, Minutes of Last Meeting, Reports of Officers, Reports of Committees, Scholarship Reports, Old Business, New Business, Announcements, Examination on Assigned Material, Guest Speakers, Assignments.

Separation of concerns - Single Responsibility Principle

SOC: Divide your app into distinct features with as little overlap in functionality as possible. SRP: The single responsibility principle states that every module or class should have responsibility over a single part of the functionality provided by the software, and that responsibility should be entirely encapsulated by the class. All its services should be narrowly aligned with that responsibility. Robert C. Martin expresses the principle as follows:[1] A class should only have one reason to change.

Sum of geometric series?

S_n = a_1(1-r^n)/(1-r)

Sum of an arithmetic sequence?

S_n = terms(a_1 + a_n) / 2

What is a regular expression?

Search pattern matching for strings. (A sequence of characters that define a search pattern, mainly for use in pattern matching with strings, or string matching, i.e. "find and replace"-like operations.)

RegExp.prototype.test()

Search regexp return boolean (The text() method executes a search for a match between a regular expression and a specified string. Returns true or false. var str = "hello world!"; var result = /^hello/.test(str); console.log(result); // true)

Array Iteration methods

Several methods take as arguments functions to be called back while processing the array. When these methods are called, the length of the array is sampled, and any element added beyond this length from within the callback is not visited. Other changes to the array (setting the value of or deleting an element) may affect the results of the operation if the method visits the changed element afterwards. While the specific behavior of these methods in such cases is well-defined, you should not rely upon it so as not to confuse others who might read your code. If you must mutate the array, copy into a new array instead.

What is the difference between a deep copy and a shallow copy?

Shallow copies duplicate as little as possible. A shallow copy of a collection is a copy of the collection structure, not the elements. With a shallow copy, two collections now share the individual elements. Deep copies duplicate everything. A deep copy of a collection is two collections with all of the elements in the original collection duplicated.

Why is the following true? 2(x + y) = 2x + 2y

Since they distributed through the parentheses, this is true by the Distributive Property.

A Simple Way to Make a Good First Impression

Smile

SNORT

Snort is an open source network intrusion prevention system, capable of performing real-time traffic analysis and packet logging on IP networks. It can perform protocol analysis, content searching/matching, and can be used to detect a variety of attacks and probes, such as buffer overflows, stealth port scans, CGI attacks, SMB probes, OS fingerprinting attempts, and much more.

greek alphabet

alpha beta gamma delta epsilon zeta eta theta iota kappa lambda mu nu xi omicron pi rho sigma tau upsillon phi chi psi omega

ctrl+ws

Split windows

ctrl+wv

Split windows vertically

Remember names and use them - Ken Nottingham

Story of addressing people with their names over the counter as a sign of endearment.

Become genuinely interested in people - Theodore Roosevelt

Story of the bobwhite and the valet's wife.

4 Ways to convert number 123 or variable N to a string

String(123); N.toString(); "" + 123; N + ""

What are all of String.prototype properties?

String.prototype.constructor - specifies the function that creates an object's prototype. String.prototype.length, N (Used to access the character in the Nth position where N is a positive integer between 0 and one less than the value of length. These properties are read-only.), constructor

How to make a string into an array of chars?

String.prototype.split('');

Can strings be changed?

Strings are immutable :(

Supervised learning

Supervised learning is a type of machine learning algorithm that uses a known dataset (called the training dataset) to make predictions. The training dataset includes input data and response values. From it, the supervised learning algorithm seeks to build a model that can make predictions of the response values for a new dataset. A test dataset is often used to validate the model. Using larger training datasets often yield models with higher predictive power that can generalize well for new datasets. Called Supervised learning BECAUSE the data is labeled with the "correct" responses.

Haskell: :t length returns length :: [a] -> Int => wtf is the [a]?

alpha type, meaning its polymorphic

Target Function definition?

Target function: In predictive modeling, we are typically interested in modeling a particular process; we want to learn or approximate a particular function that, for example, let's us distinguish spam from non-spam email. The target function f(x) = y is the true function f that we want to model. The target function is the (unknown) function which the learning problem attempts to approximate.

ES6: Template Literals

Template literals are enclosed by the back-tick (` `) (grave accent) character instead of double or single quotes. Template literals can contain place holders. These are indicated by the Dollar sign and curly braces (${expression}). The expressions in the place holders and the text between them get passed to a function. The default function just concatenates the parts into a single string. If there is an expression preceding the template literal (tag here), the template string is called "tagged template literal". In that case, the tag expression (usually a function) gets called with the processed template literal, which you can then manipulate before outputting.

The Node - King Analogy

That's right, everything runs in parallel, except your code. To understand that, imagine your code is the king, and node is his army of servants. The day starts by one servant waking up the king and asking him if he needs anything. The king gives the servant a list of tasks and goes back to sleep a little longer. The servant now distributes those tasks among his colleagues and they get to work. Once a servant finishes a task, he lines up outside the kings quarter to report. The king lets one servant in at a time, and listens to things he reports. Sometimes the king will give the servant more tasks on the way out. Life is good, for the king's servants carry out all of his tasks in parallel, but only report with one result at a time, so the king can focus. *

Distributive Property

The Distributive Property is easy to remember, if you recall that "multiplication distributes over addition". Formally, they write this property as "a(b + c) = ab + ac". In numbers, this means, that 2(3 + 4) = 2×3 + 2×4. Any time they refer in a problem to using the Distributive Property, they want you to take something through the parentheses (or factor something out); any time a computation depends on multiplying through a parentheses (or factoring something out), they want you to say that the computation used the Distributive Property.

EventTarget.addEventListener()

The EventTarget.addEventListener() method registers the specified listener on the EventTarget it's called on. The event target may be an Element in a document, the Document itself, a Window, or any other object that supports events (such as XMLHttpRequest). target.addEventListener(type, listener[, options]); target.addEventListener(type, listener[, useCapture]); type A string representing the event type to listen for. listener The object that receives a notification (an object that implements the Event interface) when an event of the specified type occurs. This must be an object implementing the EventListener interface, or simply a JavaScript function.

Node.insertBefore()

The Node.insertBefore() method inserts the specified node before the reference node as a child of the current node.

Object.defineProperty() Needs MUCH MORE ELABORATION

The Object.defineProperty() method defines a new property directly on an object, or modifies an existing property on an object, and returns the object.

String.prototype.charAt()

The charAt() method returns the specified character from a string.

String.prototype.charCodeAt()

The charCodeAt() method returns an integer between 0 and 65535 representing the UTF-16 code unit at the given index (the UTF-16 code unit matches the Unicode code point for code points representable in a single UTF-16 code unit, but might also be the first code unit of a surrogate pair for code points not representable in a single UTF-16 code unit, e.g. Unicode code points > 0x10000). If you want the entire code point value, use codePointAt().

Cocktail party effect/problem

The cocktail party effect is the phenomenon of being able to focus one's auditory attention on a particular stimulus while filtering out a range of other stimuli, much the same way that a partygoer can focus on a single conversation in a noisy room. Example of source separation.

Is the code in a function executed when the function is defined?

The code in a function is not executed when the function is defined. It is executed when the function is invoked.

String.prototype.codePointAt()

The codePointAt() method returns a non-negative integer that is the Unicode code point value.

for...of loop

The for...of statement creates a loop iterating over iterable objects (including Array, Map, Set, String, TypedArray, arguments object and so on), invoking a custom iteration hook with statements to be executed for the value of each distinct property.

Where does fullName function belong to?

The function belongs to the object.

Variables that are created within code and not within a function is always attached to...

The global object

Frat is

colloquial

Send both outputs to same file

command 1> filenae 2> &1

What is the equivalent of a constructor in JS?

The constructor is called at the moment of instantiation (the moment when the object instance is created). The constructor is a method of the class. In JavaScript the function serves as the constructor of the object, therefore there is no need to explicitly define a constructor method. Every action declared in the class gets executed at the time of instantiation. The constructor is used to set the object's properties or to call methods to prepare the object for use. Adding class methods and their definitions occurs using a different syntax described later in this article.

ES6: What there's a constructor keyword now?

The constructor method is a special method for creating and initializing an object created with a class. There can only be one special method with the name "constructor" in a class. A SyntaxError will be thrown if the class contains more than one occurrence of a constructor method.

What does the derivative of a function tell us?

The derivative of a function of a real variable measures the sensitivity to change of a quantity (a function value or dependent variable) which is determined by another quantity (the independent variable). Derivatives are a fundamental tool of calculus. For example, the derivative of the position of a moving object with respect to time is the object's velocity: this measures how quickly the position of the object changes when time is advanced. The derivative of a function of a single variable at a chosen input value, when it exists, is the slope of the tangent line to the graph of the function at that point. The tangent line is the best linear approximation of the function near that input value. For this reason, the derivative is often described as the "instantaneous rate of change", the ratio of the instantaneous change in the dependent variable to that of the independent variable.

Lazy Evaluation vs Short Circuiting?

The difference is that in case of lazy evaluation an expression is evaluated only when it is needed, while in case of short-circuit evaluation expression evaluation stops right after you know the result. It's sort of orthogonal notions.

String.prototype.endsWith()

The endsWith() method determines whether a string ends with the characters of another string, returning true or false as appropriate. str.endsWith(searchString[, position])

what is "main" in NPM package.json?

The entry point of the module. It is what is executed when someone requires the module.

AJS: Eval function? What's it do? Why is it good or bad?

The eval() function evaluates JavaScript code represented as a string. It's a way to cheat Lexical Scope "The eval(..) function in JavaScript takes a string as an argument, and treats the contents of the string as if it had actually been authored code at that point in the program. " Excerpt From: Riley Gelwicks. "You Dont Know JS by Kyle Simpson." iBooks. "function foo(str, a) { eval( str ); // cheating! console.log( a, b ); } var b = 2; foo( "var b = 3;", 1 ); // 1, 3" Excerpt From: Riley Gelwicks. "You Dont Know JS by Kyle Simpson." iBooks.

String.prototype.indexOf()

The indexOf() method returns the index within the calling String object of the first occurrence of the specified value, starting the search at fromIndex. Returns -1 if the value is not found. str.indexOf(searchValue[, fromIndex])

what does jQuery() return?

The jQuery Object: The Wrapped Set: Selectors return a jQuery object known as the "wrapped set," which is an array-like structure that contains all the selected DOM elements. You can iterate over the wrapped set like an array or access individual elements via the indexer ($(sel)[0] for example). More importantly, you can also apply jQuery functions against all the selected elements. The jQuery object itself behaves much like an array; it has a length property and the elements in the object can be accessed by their numeric indices [0] to [length-1]. Note that a jQuery object is not actually a Javascript Array object, so it does not have all the methods of a true Array object such as join().

String.prototype.lastIndexOf()

The lastIndexOf() method returns the index within the calling String object of the last occurrence of the specified value, searching backwards from fromIndex. Returns -1 if the value is not found. str.lastIndexOf(searchValue[, fromIndex])

String.prototype.localeCompare()

The localeCompare() method returns a number indicating whether a reference string comes before or after or is the same as the given string in sort order. The new locales and options arguments let applications specify the language whose sort order should be used and customize the behavior of the function. In older implementations, which ignore the locales and options arguments, the locale and sort order used are entirely implementation dependent. referenceStr.localeCompare(compareString[, locales[, options]])

Multi line flag definition

The m flag is used to specify that a multiline input string should be treated as multiple lines. If the m flag is used, ^ and $ match at the start or end of any line within the input string instead of the start or end of the entire string.

String.prototype.match()

The match() method retrieves the matches when matching a string against a regular expression. str.match(regexp)

String.prototype.repeat()

The repeat() method constructs and returns a new string which contains the specified number of copies of the string on which it was called, concatenated together. str.repeat(count)

What is private about a nested function?

The nested (inner) function is private to its containing (outer) function. It also forms a closure. A closure is an expression (typically a function) that can have free variables together with an environment that binds those variables (that "closes" the expression).

What is a nodeType in regards to DOM nodes?

The nodeType property can be used to distinguish different kind of nodes, such that elements, text and comments, from each other. -- basically a number system for the types of nodes there are.

String.prototype.normalize()

The normalize() method returns the Unicode Normalization Form of a given string (if the value isn't a string, it will be converted to one first). str.normalize([form])

Matrix multiplication?

The number of columns of the 1st matrix must equal the number of rows of the 2nd matrix. And the result will have the same number of rows as the 1st matrix, and the same number of columns as the 2nd matrix. remember matrix multiplication does not have the commutative property. Use the Dot Product to get each value for matrix multiplication.

What is the difference between Object.create() and new?

The object used in Object.create actually forms the prototype of the new object, whereas in the new Function() form, the declared properties/functions do not form the prototype. With constructor functions, the newly created object inherits from the constructor's prototype when using new. var o = new SomeConstruct(); --> inheriting from SomeConstructor.prototype.

Partial derivative notation?

The partial derivative of z with respect to x. Remember that the partial derivative is a derivative of one variable wiht others held in constant.

Does a declared function like the previous one belong to any object?

The previous function does not belong to any object. But in JavaScript there is always a default global object.

What is the purpose of the *delete* operator?

The purpose of the delete operator is to completely remove a property from an object, whereas setting a property to undefined just sets the property to undefined.

String.prototype.replace()

The replace() method returns a new string with some or all matches of a pattern replaced by a replacement. The pattern can be a string or a RegExp, and the replacement can be a string or a function to be called for each match. str.replace(regexp|substr, newSubStr|function)

What's special about Array.prototype.slice()?

The slice function is intentionally generic; it does not require that its <this> value be an Array object. Therefore it can be transferred to other kinds of objects for use as a method. Whether the slice function can be applied successfully to a host object is implementation-dependent.

String.prototype.slice()

The slice() method extracts a section of a string and returns a new string. str.slice(beginSlice[, endSlice])

ES6: Spread operator

The spread operator allows an expression to be expanded in places where multiple arguments (for function calls) or multiple elements (for array literals) or multiple variables (for destructuring assignment) are expected. it is practical for fixing cases where you have to use .apply in "hacky" sort of ways particularly when you are manipulating or using the <arguments> object and want to use arguments as an array.

String.fromCharCode()

The static String.fromCharCode() method returns a string created by using the specified sequence of Unicode values.

String.raw()

The static String.raw() method is a tag function of template literals, similar to the r prefix in Python or the @ prefix in C# for string literals (yet there is a difference: see explanations in this issue). It's used to get the raw string form of template strings (that is, the original, uninterpreted text). String.raw(callSite, ...substitutions) String.raw`templateString`

String.prototype.substr()

The substr() method returns the characters in a string beginning at the specified location through the specified number of characters. str.substr(start[, length])

String.prototype.substring()

The substring() method returns a subset of a string between one index and another, or through the end of the string. str.substring(indexStart[, indexEnd])

What is SSE?

The sum of squared error

What is "this" this time?

The thing called this, is the object that "owns" the JavaScript code. In this case the value of this is myObject.

Don't Criticize, Condemn, or Complain - Self-justification examples

Two Gun Crowley, Al Capone, Dutch Schultz

Send different ouputs to different files

command 1> stdout_filename 2> stderr_filename.

What is the value of "this" in a function constructor?

The this keyword in the constructor does not have a value. The value of this will be the new object created when the function is invoked.

String.prototype.toLocaleLowerCase()

The toLocaleLowerCase() method returns the calling string value converted to lower case, according to any locale-specific case mappings. str.toLocaleLowerCase()

String.prototype.toLocaleUpperCase()

The toLocaleUpperCase() method returns the calling string value converted to upper case, according to any locale-specific case mappings. str.toLocaleUpperCase()

String.prototype.toLowerCase()

The toLowerCase() method returns the calling string value converted to lowercase. str.toLowerCase()

String.prototype.toString()

The toString() method returns a string representing the specified object. str.toString()

String.prototype.toUpperCase()

The toUpperCase() method returns the calling string value converted to uppercase. str.toUpperCase()

What does the URL module do?

The url module provides methods which allow us to extract the different parts of a URL (like e.g. the requested path and query string), and querystring can in turn be used to parse the query string for request parameters:

AJS: <with> keyword

The with statement extends the scope chain for a statement.

AJS: With function?

The with statement extends the scope chain for a statement. One way to create dynamic scope "with is typically explained as a short-hand for making multiple property references against an object without repeating the object reference itself each time." Excerpt From: Riley Gelwicks. "You Dont Know JS by Kyle Simpson." iBooks.

you can take input in

command < input_text_or_file

character literals in C++

completely distinct from string literals - and always enclosed in single quotes whereas strings are always enclosed in double quotes.

/bin

This directory contains executable files necessary to manage and run the Linux system, including shells (such as bash) and file system management utilities such as cp and rm.

/sys

This directory contains information about the ahrdware in your system.

/dev

This directory contains special files that are used to represent the various hardware devices installed in the system. For example, the first hard disk drive in your system is called sda, the second is called sdb, and so on. The partiitions on each drive are identitfied by an additional number added to the end of the disk filename.

/home

This directory contains subdirectories that serve as home directories for each user acccount on your linux system

/var

This directory contains variable data including your system log files.

/boot

This directory contains your bootloader files, which are required to boot your system.

/root

This directory is root user's home directory. separated form other directories.

/mnt

This directory is used to mount external devices including CD drives, USB, etc as the/media directory -- this uses subdirectories for this.

JS Precedence: Exponentiation vs Multiplication? ** vs *

Tie

sections of man pages

Title, name, synopsis, author, reporting bugs, copyright, see aloso, version number and reivision date

True or false? In a nested function, the inner function has access to the outer function's variables and arguments

True

Matrix Addition & Subtraction rules?

Two matrices may be added or subtracted only if they have the same dimension; that is, they must have the same number of rows and columns. Addition or subtraction is accomplished by adding or subtracting corresponding elements. For example, consider matrix A and matrix B.

ES6: Why is the scope of the arrow function particularly useful?

Typically, Javascript functions create new scopes with a new this binding. Arrow functions support "lexical" this meaning that a new "this" is not binded, instead it uses the "This" of the function that encloses it. Problem: function Person() { // The Person() constructor defines `this` as an instance of itself. this.age = 0; setInterval(function growUp() { // In non-strict mode, the growUp() function defines `this` // as the global object, which is different from the `this` // defined by the Person() constructor. this.age++; }, 1000); } var p = new Person(); Old fix: function Person() { var self = this; // Some choose `that` instead of `self`. // Choose one and be consistent. self.age = 0; setInterval(function growUp() { // The callback refers to the `self` variable of which // the value is the expected object. self.age++; }, 1000); }

$EUID

UID of current user

Voting privileges at the Convention

UNdergraduate chatper delegeates, members of general council, past presidents of general council, province presidents, survey commissioners, the executive vice president, the housing commissioner, other commissioners taht the general council may appoint, alumni club delegates.

Solid-state media?

USB Flash, CompactFlash, Secure Digital (SD)

Value of <this> function f2(){ "use strict"; // see strict mode return this; }

Undefined (In strict mode, the value of this remains at whatever it's set to when entering the execution context. If it's not defined, it remains undefined. It can also be set to any value, such as null or 42 or "I am not this"., this should be undefined, because f2 was called directly and not as a method or property of an object (e.g. window.f2()). This feature wasn't implemented in some browsers when they first started to support strict mode. As a result, they incorrectly returned the window object.)

AJS: What's the difference between undeclared and undefined?

Undefined IS a value -- empty placeholder -- indicates that there was a declared variable. Undeclared means it hasnt been registered in the scope when the compiler runs through in phase 1.

Virtualmin

Virtualmin is a powerful and flexible web hosting control panel for Linux and UNIX systems based on the well-known Open Source web-based systems management GUI, Webmin. Manage your virtual domains, mailboxes, databases, applications, and the entire server, from one comprehensive and friendly interface.

Unsupervised learning

Unsupervised learning is the machine learning task of inferring a function to describe hidden structure from unlabeled data. Since the examples given to the learner are unlabeled, there is no error or reward signal to evaluate a potential solution. This distinguishes unsupervised learning from supervised learning and reinforcement learning. Unsupervised learning is closely related to the problem of density estimation in statistics.[1] However unsupervised learning also encompasses many other techniques that seek to summarize and explain key features of the data.

$PATH

Use $PATH to put shell scripts into and run directly from bash

What to do when J(Theta) is moving up and down in waves ?

Use a smaller Alpha!!

Normal Reload

Use cache, revalidate everything (Normal browsing, The same thing as pressing F5. This will use the cache but revalidate everything during page load, looking for "304 Not Modified" responses. If the browser can avoid re-downloading cached JavaScript files, images, text files, etc. then it will.)

What might happen if we use the window object as a variable?

Using the window object as a variable can easily crash your program.

Primitive parameters are passed to to functions by...

Value. the value is passed to the function, but if the function changes the value of the parameter, this change is not reflected globally or in the calling function. (If you pass an object (i.e. a non-primitive value, such as Array or a user-defined object) as a parameter and the function changes the object's properties, that change is visible outside the function, as shown in the following example:)

Value of <this>

Who printed the first manual

Walter B Palmer, Emory-Vanderbilt 1877

picture

Walter B Palmer, Emory-Vanderbilt 1877 at General Convention 1902

Second Founders

Walter B Palmer, Emory-Vanderbilt 1877, Georga Banta Sr., Franklin-Indiana, 1876

Second founders?

Walter B Palmer, Emory-Vandrbilt 1877 and George Banta Sr. Franklin-Indiana 1876

Alt+Enter or ⌥-Enter

WebStorm has a great number of intentions to help you quickly apply fixes, generate code, or change some project settings. Place the caret on highlighted or underlined code, and press Alt+Enter to see the list of available intention actions. For example:

Webmin

Webmin is a web-based interface for system administration for Unix. Using any modern web browser, you can setup user accounts, Apache, DNS, file sharing and much more. Webmin removes the need to manually edit Unix configuration files like /etc/passwd, and lets you manage a system from the console or remotely. See the standard modules page for a list of all the functions built into Webmin, or check out the screenshots.

Webpack?

Webpack is a powerful module bundler. A bundle is a JavaScript file that incorporate assets that belong together and should be served to the client in a response to a single file request. A bundle can include JavaScript, CSS styles, HTML, and almost any other kind of file. Webpack roams over your application source code, looking for import statements, building a dependency graph, and emitting one (or more) bundles. With plugin "loaders" Webpack can preprocess and minify different non-JavaScript files such as TypeScript, SASS, and LESS files. We determine what Webpack does and how it does it with a JavaScript configuration file, webpack.config.js.

True friendship will raise the question

What can I give? rather than What is in it for me?

/etc/X11/XF86Config

conf for xf86

How does Array.prototype.slice.call(arguments) work?

What happens under the hood is that when .slice() is called normally, this is an Array, and then it just iterates over that Array, and does its work. How is this in the .slice() function an Array? Because when you do: object.method(); ...the object automatically becomes the value of this in the method(). So with: [1,2,3].slice() ...the [1,2,3] Array is set as the value of this in .slice(). But what if you could substitute something else as the this value? As long as whatever you substitute has a numeric .length property, and a bunch of properties that are numeric indices, it should work. This type of object is often called an array-like object. The .call() and .apply() methods let you manually set the value of this in a function. So if we set the value of this in .slice() to an array-like object, .slice() will just assume it's working with an Array, and will do its thing. Take this plain object as an example. var my_object = { '0': 'zero', '1': 'one', '2': 'two', '3': 'three', '4': 'four', length: 5 }; This is obviously not an Array, but if you can set it as the this value of .slice(), then it will just work, because it looks enough like an Array for .slice() to work properly. var sliced = Array.prototype.slice.call( my_object, 3 ); Example: http://jsfiddle.net/wSvkv/ As you can see in the console, the result is what we expect: ['three','four']; So this is what happens when you set an arguments object as the this value of .slice(). Because arguments has a .length property and a bunch of numeric indices, .slice() just goes about its work as if it were working on a real Array.

What does this refer to if a function is called without an owner object?

When a function is called without an owner object, the value of this becomes the global object.

Haskell: What character denotes function application?

Whitespace

Smile - Dog

Why are dogs so loved? They do not desire anything but are so naturally glad to see people. This same love is reciprocated.

Say there are four DB Queries, one takes 200ms, the second takes 400ms, the third takes 600 ms, the fourth takes 800ms - how does node shine in this case?

With node, you can execute all your queries at once, reducing the response time to the duration it takes to execute the slowest query. -- 800MS - whereas in other non asynchronous platforms it would take 200+400+600+800 unless specifically made to run in parallel

console.assert(expression, object)

Writes error to the console when the evaluated expression is false. (https://developers.google.com/web/tools/chrome-devtools/debug/console/console-reference#assert)

"doomoom oom".match(/oom\b/g)

["oom", "oom"]

"moon".match(/oon\b/)

["oom"]

"possibly yesterday".match(/ye\B/)

["ye"]

"yoo".match(/yo\B/);

["yo"]

[1, 2, 3, 4, 5].copyWithin(-2);

[1, 2, 3, 1, 2]

Graphical Desktop Components

X server, Window Manager, Desktop environment

Konsole Terminal

X terminal emulator for KDE

X && Y equivalent?

X ∧ Y (called wedge)

X || Y equivalent?

X ∨ Y (called Vee)

Can a function have more than one tail call?

Yes

Can a function have more than one tail position?

Yes

Is the current directory dot necessary when importing modules in Node?

Yes.

Smile - Meetings

You MUST have a good time meeting people if you expect them to have a good time meeting you.

[1,2,3,4,5].copyWithin(0,3,4);

[4, 2, 3, 4, 5] (target Zero based index at which to copy the sequence to. If negative, target will be counted from the end. If target is at or greater than arr.length, nothing will be copied. If target is positioned after start, the copied sequence will be trimmed to fit arr.length. start Zero based index at which to start copying elements from. If negative, start will be counted from the end. If start is omitted, copyWithin will copy from the start (defaults to 0). end Zero based index at which to end copying elements from. copyWithin copies up to but not including end. If negative, end will be counted from the end. If end is omitted, copyWithin will copy until the end (default to arr.length).)

Reiser

alternative to ext3, utilizes journaling as well -- but uses a dramatically different internal structure.

command substitution

alternative to piping tail$(fgrep -l 192.168 /etc/*) -- command returns a list of filenmames only not the actual matching text. list of files is then piped to input of tial command

Female graduate

alumna

Plural for female graduate

alumnae (pronounced alumnee)

Plural for male graduate

alumni

Exit status 0

always means the command exited successfully without any errors. an exit status of nany numbe rother than 0 indicates an error of some type that occurred and that the command exited abnormally.

x^i_j notation in ML means?

an index into a training set for the ITH training example and JTH feature (input variable)

append after the cursor

append at end of word

append at the end of the line

VI : a

appends text after cursor

VI : A

appends text to end of current line

List all the properties of the arguments keyword

arguments.callee, arguments.length, arguments[@@iterator]. (arguments.caller is deprecated due to security vulnerabilities)

Write a function that returns does this given an array of 3 arrays of 3 ints [[5,3,7],[3,3,1],[4,1,2]] == ((5+3+7) * (3+3+1) * (4+1+2)) = 735

arr.map(a=>a.reduce((x,y)=>x+y),0).reduce((a,b)=>a*b); arr.map( a => a[0] + a[1] + a[2]).reduce( (a,b) => a * b); (important thing to note here is the use of mapping and reducing together, the map allows you to reduce on each element)

Sum up an array named arr

arr.reduce( (prev, curr) => prev + curr );

Combine the following arrays: let arr1 = [1,2,3]; let arr2 = [2,3,4]; let arr3 = [5,6,7];

arr1.concat(arr2,arr3);

Delete all numbers that are greater than 5 in this array: let arr1 = [4,7,9,1];

arr1.filter( num => num <= 5);

What does str.prototype.match(RegExp) return?

array match result else null (An Array containing the entire match result and any parentheses-captured matched results, or null if there were no matches.)

multivariate linear regression

ask: why is the notation shorter and what does that convenience notation indicate?

sudo

become super user root

miami triad

beta theta pi, phi delta theta, sigma chi

subdirectories of /usr

bin, lib, lib64, local, sbin, share

What do both of the methods have to have?

both methods must have the owner object as first parameter.

function foo(){ return 1 + bar(); } what's wrong with this?

can be optimized. currently storing frames onto stack during recursion due to "1 +"

ext4

can support up to 16TB. very big, -- uses checksums in addition to journaling.

i flag

case-insensitive search

change (replace) to the end of line

change (replace) to the end of word

change directory

: chgrp

change group that owns a file or directory

: passwd

change iexisting user's passwords.

: chmod

change permsisions chmod entity=[ermissions filename or use numbers in octal

POWER_GOOD

checks for right voltage and shuts off motherboard in this case

BIOS

chip containing series of very small programs that allows system to function

var fruits = ['Banana', 'Orange', 'Lemon', 'Apple', 'Mango']; var citrus = fruits.slice(1, 3); value of citrus?

citrus contains ['Orange','Lemon']

(C++) Write a Class Box with the public properties length breadth height as doubles. Then instantiate two boxes as Box1 and Box2

class Box { public: double length; // Length of a box double breadth; // Breadth of a box double height; // Height of a box }; Box Box1; // Declare Box1 of type Box Box Box2; // Declare Box2 of type Box

$HISTCONTROL

controls how command history is stored

/etc/ftpusers

controls user access to the ftp service running on system

VI: yy

copies line in which cursor is located to buffer

copy file or directory

: dd

copy with dd determine input and outut file -- it copies data using records with default size of record being 512. because of this it can copy an entire parititon to a single file.

alpha delta phi

counted as the first sisterhood having been founded as the adelphean society in 1851.

How to make sure gradient descent is working properly?

create an automatic convergence test - declare convergence based on amount of decrease of J(Theta) plot on graph, y axis being J and axis being number of iterations.

Motherboard

creates electrical path that connect everything together

$USER

current user

: cut

cut columsns or fields that you specify form a file -c(list) - select only these characters -d(delim) - use specified character isntead of tab for delimiter -f(list) -- select only specified fields -s do not print lines that do not contain these delimiters

PICO: CTRL-K / CTRL-U

cuts and pastes

when was phi beta kappa founded?

december 5 1776 at the college of william and mary in williamsburg, virginia, the second-oldest institution for higher learning in America. -- in Old Raleigh Tavern

: declare -i

declare a variable to be a certain type - typecasting --i in this case is for an integer.

Data Link

defines rules and procedures for accessing the physical layer. it defines how hosts are identified on the network and how the network medium is accessed. it also sepecified how to verify that the data received from the physical layer doesn't have any errors. information received from upper layers is orrganized into datagrams

delete (cut) current character

delete (cut) the current word

:bd

delete a buffer (close a file)

: userdel

delete a user, simply enter userdel username. -r removes home directory.

: groupdel

delete an existing project from the system

delete character at cursor and subsitute text

delete line at cursor and substitute text (same as cc)

delete marked text

given an array of objects: var numbers = [{ name: 'Mark' },{ name: 'Tom' },{ name: 'Travis' }]; write a function that will iterate across and print each name using <this>

for (var i = 0; i < numbers.length; i++) { (function () { console.log(this.name); // Mark, Tom, Travis }).call(numbers[i]); }

/etc/init.d

for init scripts on BSD style systems

etc/rc.d

for system V init scripts

Init Scripts

for system processes you use an init script which is used by the init process to start processes on system boot.

why use Array.prototype.forEach when iterating with side effects?

forEach has an "undefined" return value always. MAP, being a functional programming method is much better suited when creating a pure function. For non-pure iterative functions forEach makes sense. The predicate here should produce a side effect. immutability is promoted with FP and can be exhibited when using map. That is map doesnt mutate the given array, only creates a new array as a copy of the given and then modifies it. example: function logValue(v) {console.log(v);} forEach(arr,logValue);

: free

free command displays the amount of free and allocated RAM and swap memotry in your system use the -m option to display memory statistics in megabytes -t option to fdisplay totals for each category of information

Import the linear regression class from Scikit

from sklearn.linear_model import LinearRegression

There's no such thing as private properties on a coffeescript object! But, maybe there are? Implement a function createSecretHolder(secret) which accepts any value as secret and returns an object with ONLY two methods getSecret() which returns the secret setSecret() which sets the secret

function createSecretHolder(secret) { let _val = secret; return { getSecret : function() { return _val; }, setSecret: function(s) { _val = s; } }

Write a function that doubles each char in a given string using regexp

function doubleChar(str) { return str.replace(/(.)/g, "$1$1") }

map(function(x) {return x * x * x}, [0, 1, 2, 5, 10]); --> function expression or declaration?

function expression

Write a function length that recursively finds the length of a linked list

function length(head) { head ? 1 + length(head.next) : 0; }

Write function map(f,a) {};

function map(f,a){ var result =[], i; for (i = 0; i != a.length; i++){ result[i] = f(a[i]); } return result; }

what's wrong with this recursive function? var tracker = 0; var callMe = function() { tracker++ if (tracker === 3) { return 'loops!'; } callMe('anytime'); }; why doesn't it return 'loops'?

it returns undefined since 'loops' isnt worked back up the call stack. the third call of callMe() does return 'loops', but the second call of callMe() doesn't use that anywhere.

var firstFn = function () { var localToFirstFn = 'first'; // Although false, it might seem reasonable to think that the secondFn (which mentions the localToFirstFn variable), should have access to the localToFirstFn variable, since it's being called here from within the scope where that variable is declared. secondFn(); }; var secondFn = function () { ACTUAL = localToFirstFn; }; //value of ACTUAL?

it('a function\'s local scope variables are not available anywhere outside that function, regardless of the context it\'s called in', function () {

var sameName = 'outer'; var fn = function () { var sameName = 'inner'; ACTUAL = sameName; }; fn();

it('if an inner and an outer variable share the same name, and the name is referenced in the inner scope, the inner scope variable masks the variable from the outer scope with the same name. This renders the outer scope variables inaccassible from anywhere within the inner function block', function () {

function () { var sameName = 'outer'; var fn = function () { var sameName = 'inner'; }; fn(); ACTUAL = sameName; expect(ACTUAL === 'outer').to.be.true; });

it('if an inner and an outer variable share the same name, and the name is referenced in the outer scope, the outer value binding will be used',

var sameName = 'outer'; var fn = function () { var sameName = 'inner'; }; fn(); ACTUAL = sameName; expect(ACTUAL === 'outer').to.be.true;

it('if an inner and an outer variable share the same name, and the name is referenced in the outer scope, the outer value binding will be used', function () {

: join

join prints line from each of two speciied input fields based on delimiters

jump backward by words (no punctuation)

jump by start of words (punctuation considered words)

jump by words (spaces separate words)

jump to end of words (no punctuation)

.ko or .o

kernel module (driver) extension

Two ways Linux implements drivers

kernel module loading. Driver loading once the linux kernel has been loaded into memory. kernel modules have a .ko or .o extension second way is to compile the necessary driver support within the kernel. requires to manually recompile the kernel. -- not a good idea because it takes a lot of time and dedication. and its a good idea to keep kernel as lean and clean as posssible.

: kill

kill command terminates a process use kill -signal PID.

SIGINT (2)

kill signal 2 -- sends CTRL+C to process

What is a lambda expression?

lambda expression in computer programming, also called anonymous function, a function (or a subroutine) defined, and possibly called, without being bound to an identifier Lambda Expressions are nameless functions given as constant values. They can appear anywhere that any other constant may, but are typically written as a parameter to some other function. The canonical example is that you'll pass a comparison function to a generic "sort" routine, and instead of going to the trouble of defining a whole function (and incurring the lexical discontinuity and namespace pollution) to describe this comparison, you can just pass a lambda expression describing the comparison. HOWEVER, this misses one of the most important features of Lambda Expressions, which is that they execute in the context of their appearance. Therefore, they can use the values of the variables that are defined in that context. This differentiates function-pointers from true lambda expressions. In languages supporting mutable variables, proper lambda expressions offer the power change the values of those variables. Lambda expressions are rooted in lambda calculus.

ES6: This is used to work around the <this> bindings in JS What ES6 feature fixes this? and how can it be rewritten? let sum = function(){ return Array.prototype.reduce.call(arguments,(prev,curr) => {prev+curr}); } sum(2,3,4,5);

let sum = function(...args){ return args.reduce((prev,curr) => prev + curr); }

in JavaScript, the scope of a variable is defined by its location within the source code (it is apparent) and nested functions have access to variables declared in their outer scope.

lexical scope & static scope

What is libuv?

libuv is a multi-platform support library with a focus on asynchronous I/O. It was primarily developed for use by Node.js, but it's also used by Luvit, Julia, pyuv, and others.

: netstat

list network connections, display routing table, display info about network interface -a lists all listening and nonlistening sockets -i displays statistics for your network interfaces

Haskell: convention meaning: xs, ns, nss

list of type s, list of type n, list of lists of type s

/etc/fstab

lists partitions and file systems that are mounted when system boots

: nice

nice utility used to launch processes with different priority levels changes the NI value which is value of process factored into kernel calculations that determines the priority (R) " nice -n nice_level command" must be root for nice to be set to below 0

Change double quotes to single quotes on a word

no need to visual select just do cs"' -- so cs <need to change delimiters> with <to changed delimiters>

function add(a, b) {return a +b; } //has a scope been created?

no. scopes are only created when the function is run or invoked.

\B (examples needed)

non-word boundary

NIC

north-american interfraternity conference. aimed at same goals as the NPC. 1909

"moon".match(/oo\b/)

null

"yo".match(/\Byo/);

null

"yoo".match(/\Byo/);

null

Haskell: What does null do

null checks if a list is empty. If it is, it returns True, otherwise it returns False. Use this function instead of xs == [] (if you have a list called xs)

How to clear a bit

number &= ~(1 << x);

How to toggle a bit?

number ^= 1 << x;

How to set any bit?

number |= 1 << x;

SSE formula?

observation - mean for each observation squared.

topics of conersation

of less ocntroversial nature. save political debate for after hour dinners. avoid squeamish subject. avoid vulgar language.

the good man is one who is

of strong character, just and generous in his freindship, loyal and upright. friendship is born between men who share these ideals.

The good man is one..

of strong character, just and generous in his friendship, loyal and upright. Friendship is born between men who share these ideals.

additive property of permissions

one suer accountcan receiver permissions from more than one entity

function outside(x) { function inside(y) { return x + y; } return inside; } fn_inside = outside(3); result = fn_inside(5); result1 = outside(3)(5); Explain how result1 returns its value.

outside(3) returns a function that adds 3 to whatever it is given because of the closure. That is, the inside function has access to the arguments and variables of the outside function. Thus, when outside(3) returns it calls the 'add 3 to whatever' function with the value (5) thus returning 8. (Notice how x is preserved when inside is returned. A closure must preserve the arguments and variables in all scopes it references. Since each call provides potentially different arguments, a new closure is created for each call to outside. The memory can be freed only when the returned inside is no longer accessible. This is not different from storing references in other objects, but is often less obvious because one does not set the references directly and cannot inspect them.)

/dev/lp0

parallel port

INIT Process

parent process or grand-parent of all other linux processes.

$HOME

path to current user's home directory

$MAIL

path to current user's mailbox file

$PWD

path to current working directory

$OLDPWD

path to prior current directory

secrecy concerning the organization is

perpetually and wisely enjoyed in The Bond, not because secrecy is a vital factor, but it is important where friendships are so close and confidential.

/var/log/

place to store system log files

hypothesis model

remember that the HYPOTHESIS MODEL or SET is what is depicted with h(theta)

rmdr

remove directory

shift()

removes the first position of an array and returns it

pop()

removes the last position of an array and returns it

repeat last command

repeat search in opposite direction

repeat search in same direction

...

repeated

{...}

repetition

:%s/old/new/gc

replace all old with new throughout file with confirmations

Multicore CPU

replaced hyperthreading CPUs

ext2

reputed to be fastests but one off the oldest as well. has one key weakness and that is it takes long time to recover if system shuts down abruptly. -- there isn't a clean dismount procedure. -- wil run e2fsck ot fix any problems but that indexing required for e2fsck takes too long

Using RequireJS show how to import a module in AMD

require(['calculator/add'], function (add){ console.log(add(1,6)); });

: ifdown interface, ifup interface

restart your network interface to apply changes -- interface is alias of interface such as eth0

"abc def".match(/\b./) returns?

returns ["a"]; - only returns first one due to no /g flag

toString()

returns a string value of the regular expression

getDay()

returns day of the week

: uname

returns info about linux system

getTime()

returns milliseconds since 1970

getDate()

returns the calendar day number

html

root element

// this is a longer form of the same observation as above, using strings in stead of numbers. var fn = function () { var localVariable; if (localVariable === undefined) { // the variable will be initialized for the first time during this call to fn ACTUAL = 'alpha'; } else if (localVariable === 'initialized') { // the variable has already been initialized by a previous call to fn ACTUAL = 'omega'; } // now that actual has been set, we will initialize localVariable to refer to a string localVariable = 'initialized'; }; fn(); expect(ACTUAL === 'alpha').to.be.true; fn(); expect(ACTUAL === 'omega').to.be.true; //what's wrong here?

second value should be alpha

SATA

seria hard drive, not subject to master/slave config rules.

: set , :unset

set is a built-in function of the Bourne shell (sh), C shell (csh), and Korn shell (ksh), which is used to define and determine the values of the system environment.

Protocool

set of rules and in context of networking given communication rules

Linux Shells

sh, bash, csh, tsch

csh (C shell)

shell similar to C

shift left

shift right

false || null || "" || 0 || NaN || "Hello" || undefined

short circuit evaluation - returns "Hello"

1 && [] && {} && true && "World" && null && 2010 -- why is this optimized?

short circuit evaluation -- returns null and doesnt evaluate 2010;

: tail -f

show tail messages as you use the system

: history

shows history with a size determined by HISTFILESIZE

CMD: halt

shuts down OS

CMD: reboot

shuts down and restarts OS

CMD: shutdown

shutsdown computer but with advantages of specifiying time when to shut down and also sends messages to all-logged in users, blocks users to log in from the time of the pending shut down

PATA can be jumpered as what

single, master, slave, or cable select

A square matrix that is not invertible is called ..

singular or degenerate

How to trim off last letter of a string <str> using String.prototype.substr?

str.substr(0, str.length -1);

How to trim off first letter of a string <str> using String.prototype.substr?

str.substr(1);

RAID 0

striping

RAID 5

striping with parity

great snowball rebellion

students of miami blocked the entrances of the amin educational and administrative building in the winter of 1847.

: su

su substitute user, needs root's password -c command switches to user account and runs specified command -m switches to user acct but preserves existing environment variables

⊆

subset of or equal to

: sudo

sudo if in sudoers gets root permission to run a commmand requires user's password not root's

Haskell: Sum up list, length of list, product, reverse, append two lists

sum [1,2,3,4,5], product, [1,2,3,4,5] ++ [6,7,8], reverse

ctrl+ww

switch between windows

switch case

: su -

switch to root

CMD: init 6

switches system to runlevel 6 which reboots system

CMD: su

switcswitches user to a new user account

UID between 0 - 999

system accounts

Haskell: Remove first element from a list

tail [1,2,3,4,5];

Haskell: Select first N elements of a list

take 3 [1,2,3,4,5]

: | pipes

take output and put it into next command

: tar

tar options -A (appends tar files to existing archive) -d --compare compare differences between an archive file and filees in system -z uses the gzip utility to compress. -j uses bzip2 instead

: tee

tee command is to display output forom a command and also use redirection or piping

: tail /var/logmessages 1> lastmessages

tells shell to redirect stdout (1) to file named lastmessages

test()

tests a string for a matching pattern, used with regular expression

what is the difference between the function constructor and the object constructor?

they look the same.

/etc

this directory contains text-based config files used by stem as well as services running on system.

: dig

use Domain Information Groper (dig) to preferom a DNS lookup on yur DNS server and display detailed info about the hostname being resolved and about dns server itself a - resolve a record info ptr - resolve a ptr record cname - resolve cname record info in - resolve internet record info mx - resolve mx record info soa - resolve start of authority info

functions with variable number of params

use arguments

: tail -f

use it to monitor file specified continuously. -- helpful when trouble shooting

How to iterate across an object with side effects?

use the for... in loop while checking .hasOwnProperty because for...in will check parents as well.

:cut

used to print columns or fields that you specify from a file to the stdout by default tab is used as delimiteer -b select bytes -c select chars -d delim -flist -s

: tr

used to translate or delete characters -- send text stream to stin of tr.

/etc/passwd

user account info for your system

~/.bash_login

user-specific shell preferences

/etc/skel

useradd copies files from skel directory into a newly created home directory. -- contains seceral config files such as .bashrc and.profile

UID

userid

$LOGNAME

username of current user

ext3

uses journalling to fix the abrupt shutdown error of ext2-- backgrounds compatible

script can read from input of bash

using : read

slogin

utility that accesses the shell prompt remotely

Document.getElementsByClassName()

var elements = document.getElementsByClassName(names); // or: var elements = rootElement.getElementsByClassName(names); *elements* is a live HTMLCollection of found elements. *names* is a string representing the list of class names to match; class names are separated by whitespace getElementsByClassName can be called on any element, not only on the document. The element on which it is called will be used as the root of the search.

Your code (king) gives node (servants) the two tasks to read and write a file, and then goes to sleep. Once node has completed a task, the callback for it is fired. But there can only be one callback firing at the same time. Until that callback has finished executing, all other callbacks have to wait in line. In addition to that, there is no guarantee on the order in which the callbacks will fire.

var fs = require('fs') , sys = require('sys'); fs.readFile('treasure-chamber-report.txt', function(report) { sys.puts("oh, look at all my money: "+report); }); fs.writeFile('letter-to-princess.txt', '...', function() { sys.puts("can't wait to hear back from her!"); });

Show three ways to write global variables

var glob1 = 'global here'; function yolo(){ glob2 = 'global here too actually'; window.glob3 = 'global attached to window'; }

: finger

view information about the user

: fgrep

searches files for lines tha tmatch a fixed string.

SUID

When an executable file with the SUID set is run, the user who ran the file temporarily becomes the file's owner

an example of apply()

function myFunction(a, b) { return a * b; } myArray = [10,2]; myFunction.apply(myObject, myArray); // Will also return 20

Whats the difference between * and +?

(The * matches preceding expression even when not existent 0 or more times, but the + necessitates its existence that is 1 or more times.)

REGEXP reviews

* . ^ $ | [nnn] [^nnn] [n-n]

Properties of the Object built-in-type?

1. Object.length Has a value of 1. 2. Object.prototype Allows the addition of properties to all objects of type Object.

Three use cases for apply()

1. Using apply to chain constructors You can use apply to chain constructors for an object, similar to Java. In the following example we will create a global Function method called construct, which will enable you to use an array-like object with a constructor instead of an arguments list. 2. Using apply and built-in functions Clever usage of apply allows you to use built-ins functions for some tasks that otherwise probably would have been written by looping over the array values. As an example here we are going to use Math.max/Math.min to find out the maximum/minimum value in an array. (// min/max number in an array var numbers = [5, 6, 2, 3, 7]; // using Math.min/Math.max apply var max = Math.max.apply(null, numbers); // This about equal to Math.max(numbers[0], ...) // or Math.max(5, 6, ...) var min = Math.min.apply(null, numbers); // vs. simple loop based algorithm max = -Infinity, min = +Infinity; for (var i = 0; i < numbers.length; i++) { if (numbers[i] > max) { max = numbers[i]; } if (numbers[i] < min) { min = numbers[i]; } }) 3. Using apply in "monkey-patching" Apply can be the best way to monkey-patch a built-in function of Firefox, or JS libraries. Given some object.foo function, you can modify the function in a somewhat hacky way, like so: (var originalfoo = someobject.foo; someobject.foo = function() { // Do stuff before calling function console.log(arguments); // Call the function as it would have been called normally: originalfoo.apply(this, arguments); // Run stuff after, here. })

Javascript ASI (Automatic Semicolon insertion)

1. When a token (LineTerminator or }) is encountered that is not allowed by the grammar, a semicolon is inserted before it if: - The token is separated from the previous token by at least one LineTerminator. - The token is } { 1 2 } 3 // is transformed to { 1 ;2 ;} 3; The NumericLiteral 1 meets the first condition, the following token is a line terminator. The 2 meets the second condition, the following token is }. 2. When the end of the input stream of tokens is encountered and the parser is unable to parse the input token stream as a single complete Program, then a semicolon is automatically inserted at the end of the input stream. a = b ++c // is transformed to: a = b; ++c; / 3. This case occurs when a token is allowed by some production of the grammar, but the production is a restricted production, a semicolon is automatically inserted before the restricted token. ostfixExpression : LeftHandSideExpression [no LineTerminator here] ++ LeftHandSideExpression [no LineTerminator here] -- ContinueStatement : continue [no LineTerminator here] Identifieropt ; BreakStatement : break [no LineTerminator here] Identifieropt ; ReturnStatement : return [no LineTerminator here] Expressionopt ; ThrowStatement : throw [no LineTerminator here] Expression ; classic example: return "something"; // is transformed to return; "something"; (http://stackoverflow.com/questions/2846283/what-are-the-rules-for-javascripts-automatic-semicolon-insertion-asi)

Nick Reuter

1430

David Gao

1432

Chris Summers

1434

Rolland Lee

1435

SATA plugs?

15-pin power, 7-pin data

SATA speeds come in what

150,300,600 MB/s, 1.5/3.0/6.0Gb

UXGA

1600 * 1200

SCSI

160MB/s to 640 MB/s

Class B Private

172.16.0.0. - 172.31.255.255

chapters of pdt

173

majority of greek letter societies were founded

1865 - 1900

pi beta phi

1867 - first organization of college women established as a national college fratnernity.

kappa alpha theta

1870 - first greek letter society for women.

CLASS C

192.168.0.0. - 192.168.255.255

WUXGA

1920 * 1200

NPHC

1930 when founded -- national panhellenic for African aMerican

3x4 matrix * 4x1 vector result is...

3x1 matrix

F Minor

4 Flats - Bb Eb Ab Db

B Major

5 Sharps - F# C# G# D# A#

G# Minor

5 Sharps - F# C# G# D# A#

@angular/common

@angular/common - The commonly needed services, pipes and directives provided by the Angular team.

@angular/compiler

@angular/compiler - Angular's Template Compiler. It understand templates and can convert them to code that makes the app run and render. Developers typically don't interact with the compiler directly. They use it indirectly via platform-browser-dynamic or the offline template compiler.

@angular/core

@angular/core - Critical runtime parts of the framework needed by every application. Includes all metadata decorators, Component, Directive, dependency injection, and the component lifecycle hooks.

@angular/platform-browser

@angular/platform-browser - Everything DOM and browser related, especially the pieces that help render into DOM. This package also includes the bootstrapStatic method for bootstrapping applications for production builds that pre-compile templates offline.

@angular/platform-browser-dynamic

@angular/platform-browser-dynamic - Providers and a bootstrap method for applications that compile templates on the client. don't use offline compilation. We use this package for boostrapping during development and for boostrapping plunker samples

What happens if you delete an array element? var arr = [1,2,3,4]; delete arr[3];

When you delete an array element, the array length is not affected. This holds even if you delete the last element of the array. When the delete operator removes an array element, that element is no longer in the array.

What is Bower?

Bower is pretty much dead. Don't need two package managers esp. when NPM is so good and continuously getting grouped with JS overall and not just Node. But, Bower WAS a front-end package manager -- remember when I used it, it sucked. such overtooling. From MPJME: (https://www.quora.com/Why-use-Bower-when-there-is-npm) In almost all cases, it's more appropriate to use Browserify and npm over Bower. It is simply a better packaging solution for front-end apps than Bower is. At Spotify, we use npm to package entire web modules (html, css, js) and it works very well. Bower brands itself as the package manager for the web. It would be awesome if this was true - a package manager that made my life better as a front-end developer would be awesome. The problem is that Bower offers no specialized tooling for the purpose. It offers NO tooling that I know of that npm doesn't, and especially none that is specifically useful for front-end developers. There is simply no benefit for a front-end developer to use Bower over npm. With browserify or webpack, it becomes super-easy to concatenate all your modules into big minified files, which is awesome for performance, especially for mobile devices. Not so with Bower, which will require significantly more labor to get the same effect. npm also offers you the ability to use multiple versions of modules simultaneously. If you have not done much application development, this might initially strike you as a bad thing, but once you've gone through a few bouts of Dependency hell you will realize that having the ability to have multiple versions of one module is a pretty darn great feature. Note that npm includes a very handy dedupe tool that automatically makes sure that you only use two versions of a module if you actually have to - if two modules both can use the same version of one module, they will. But if they can't, you have a very handy out.

Back reference the third paren surrounded regexp

What are regex anchors?

^ $

What is the dunder proto?

__proto__

Partial derivative?

In mathematics, a partial derivative of a function of several variables is its derivative with respect to one of those variables, with the others held constant (as opposed to the total derivative, in which all variables are allowed to vary). Partial derivatives are used in vector calculus and differential geometry.

Do proper tail calls work normally in Javascript?

No, you have to turn on "strict mode"

: route del -net network_address netmask netmask gw route_address

a () block (with braces)

The else of : if (a < b) { //execute }

a >= b

Can you assign to a const after declaring the const?

No. A const promises that we won't change the value of the variable for the rest of its life and this is considered a reassignment or rewrite.

Calc

Excel Linux

AMD vs CommonJS advantages and disadvantages summary and where does ES6 modules play into this?

From Reddit: AMD is dead (was killed by Node-compatible bundlers). CommonJS is dead (was killed by Node). Node uses something that looks like CommonJS and is commonly called CommonJS but isn't actually CommonJS (there's a spec for CommonJS imports and Node knowingly violates good chunks of it). ES6 imports aren't currently natively supported in any JS engine I know of. They can however be translated to Node-style "CommonJS" and there are bundlers that support them directly. As for what CommonJS is: CommonJS was an effort to define common standards for the various competing server-side JavaScript environments that existed at the time (including well-known but now mostly obsolete stuff like Rhino as well as a few lesser known alternatives to Node that have died out). Node mostly won, so the new common standard is "whatever Node does". One of the reasons AMD failed was that it is a lot more complex than the alternative. AMD is intended to be asynchronous at runtime. This means it not only defines dependencies, it also conflates the issue of lazy loading dependency bundles. As it turned out, lazy loading dependency bundles at runtime is a difficult, rare and heterogeneous enough problem that a module system can't easily solve it. But having this kind of complexity in it meant that it was effectively overengineered for the more common simple problems. That said, if you write code today, just use either Node-style imports directly or a tool like Babel that translates ES6 imports to Node-style ones.

What is left associativity?

a Q b Q c If Q is left associative, then it evaluates as (a Q b) Q c And if it is right associative, then it evaluates as a Q (b Q c)

pandas.Series.describe

Generate various summary statistics, excluding NaN values. For numeric dtypes, it will include: count, mean, std, min, max, and lower, 50, and upper percentiles. For object dtypes (e.g. timestamps or strings), the index will include the count, unique, most common, and frequency of the most common. Timestamps also include the first and last items. For mixed dtypes, the index will be the union of the corresponding output types. Non-applicable entries will be filled with NaN. Note that mixed-dtype outputs can only be returned from mixed-dtype inputs and appropriate use of the include/exclude arguments. If multiple values have the highest count, then the count and most common pair will be arbitrarily chosen from among those with the highest count.

How to swap two values a,b using bits?

a ^= b; b ^= a; a ^= b; OR (easier to memorize) x = x xor y y = x xor y x = x xor y

SOL*I*D

ISP - Interface Segregation Principle (The interface-segregation principle (ISP) states that no client should be forced to depend on methods it does not use.)

ISPconfig

ISPConfig is an open source hosting control panel for Linux, licensed under BSD license and developed by the company ISPConfig UG. The ISPConfig project was started in autumn 2005 by the German company projektfarm GmbH.ISPConfig allows administrators to manage websites, e-mail addresses and DNS records through a web-based interface. The software has 4 login levels: administrator, reseller, client and email-user.

Array.prototype.reduce()

ITERATION method Apply a function against an accumulator and each value of the array (from left-to-right) as to reduce it to a single value.

Array.prototype.reduceRight()

ITERATION method Apply a function against an accumulator and each value of the array (from right-to-left) as to reduce it to a single value.

Array.prototype.forEach()

ITERATION method Calls a function for each element in the array.

Array.prototype.filter()

ITERATION method Creates a new array with all of the elements of this array for which the provided filtering function returns true.

Array.prototype.map()

ITERATION method Creates a new array with the results of calling a provided function on every element in this array.

Array.prototype.entries() ECMASCRIPT 6

ITERATION method Returns a new Array Iterator object that contains the key/value pairs for each index in the array. let people = ['jamie', 'jack', 'isaac']; let entries = people.entries(); console.log(entries.next().value); // [0, 'jamie'] console.log(entries.next().value); // [1, 'jack'] console.log(entries.next().value); // [2, 'isaac'] The following methods help with iterating over Arrays: Array.prototype.entries() Array.prototype.keys() Array.prototype.values() The result of each of the aforementioned methods is a sequence of values, but they are not returned as an Array; they are revealed one by one, via an iterator. Let's look at an example. I'm using Array.from() to put the iterators' contents into Arrays: > Array.from(['a', 'b'].keys()) [ 0, 1 ] > Array.from(['a', 'b'].values()) [ 'a', 'b' ] > Array.from(['a', 'b'].entries()) [ [ 0, 'a' ], [ 1, 'b' ] ]

Array.prototype.keys() ECMASCRIPT 6

ITERATION method Returns a new Array Iterator that contains the keys for each index in the array.

Array.prototype.findIndex() ECMASCRIPT 6

ITERATION method Returns the found index in the array, if an element in the array satisfies the provided testing function or -1 if not found. arr.findIndex(callback[, thisArg])

Array.prototype.find() ECMASCRIPT 6

ITERATION method Returns the found value in the array, if an element in the array satisfies the provided testing function or undefined if not found. arr.find(callback[, thisArg])

Array.prototype.some()

ITERATION method Returns true if at least one element in this array satisfies the provided testing function.

Array.prototype.every()

ITERATION method Returns true if every element in this array satisfies the provided testing function.

In JS OOP, what's a namespace?

in strict javascript mode which argument becomes the value of this?

In JavaScript strict mode, the first argument becomes the value of this in the invoked function, even if the argument is not an object. "so it creates an object from anying. "

What is the gobal object in a webrowser?

In a web browser the global object is the browser window.

Document.createElement

In an HTML document, the Document.createElement() method creates the specified HTML element or an HTMLUnknownElement if the given element name isn't a known one.

function always(n) { return function () { return n }; } why is this useful?

In an analogy with OOP, the outer function is kind of like a class constructor, and the inner function is kind of like a method and the variable n is kind of like a private variable. (function product(name, price) { var companyName = 'ACME'; return { getCompanyName: function () { return companyName }, getName: function () { return name }, getPrice: function () { return price }, setPrice: function (x) { return price = x } } } widget = product('widget', 2); widget.getCompanyName(); // 'ACME' widget.getName(); // 'widget' widget.getPrice(); // 2 widget.setPrice(5); // 5 widget.getPrice(); // 5)

Pure Function conditions

In computer programming, a function may be considered a pure function if both of the following statements about the function hold: The function always evaluates the same result value given the same argument value(s). The function result value cannot depend on any hidden information or state that may change while program execution proceeds or between different executions of the program, nor can it depend on any external input from I/O devices (usually—see below). Evaluation of the result does not cause any semantically observable side effect or output, such as mutation of mutable objects or output to I/O devices (usually—see below).

What is a side effect?

In computer science, a function or expression is said to have a side effect if it modifies some state or has an observable interaction with calling functions or the outside world. For example, a particular function might modify a global variable or static variable, modify one of its arguments, raise an exception, write data to a display or file, read data, or call other side-effecting functions. In the presence of side effects, a program's behaviour may depend on history; that is, the order of evaluation matters. Understanding and debugging a function with side effects requires knowledge about the context and its possible histories

What is a stream?

In computer science, a stream is a sequence of data elements made available over time. A stream can be thought of as items on a conveyor belt being processed one at a time rather than in large batches Streams are processed differently from batch data - normal functions cannot operate on streams as a whole, as they have potentially unlimited data, and formally, streams are codata (potentially unlimited), not data (which is finite). Functions that operate on a stream, producing another stream, are known as filters, and can be connected in pipelines, analogously to function composition. Filters may operate on one item of a stream at a time, or may base an item of output on multiple items of input, such as a moving average. - *processed one at a time rather than in batches*

What is a computer thread??

In computer science, a thread of execution is the smallest sequence of programmed instructions that can be managed independently by a scheduler, which is typically a part of the operating system.[1] The implementation of threads and processes differs between operating systems, but in most cases a thread is a component of a process. Multiple threads can exist within one process, executing concurrently and sharing resources such as memory, while different processes do not share these resources. In particular, the threads of a process share its executable code and the values of its variables at any given time. Systems with a single processor generally implement multithreading by time slicing: the central processing unit (CPU) switches between different software threads. This context switching generally happens very often and rapidly enough that users perceive the threads or tasks as running in parallel. On a multiprocessor or multi-core system, multiple threads can execute in parallel, with every processor or core executing a separate thread simultaneously; on a processor or core with hardware threads, separate software threads can also be executed concurrently by separate hardware threads.

Become genuinely interested in people - George Dyke

In his humble and friendly way he became generally interested in learning the background nad interests of every musician he met.

Haskell 98?

In late 1997, the series culminated in Haskell 98, intended to specify a stable, minimal, portable version of the language and an accompanying standard library for teaching, and as a base for future extensions. The committee expressly welcomed creating extensions and variants of Haskell 98 via adding and incorporating experimental features.

What is an identity matrix?

In linear algebra, the identity matrix, or sometimes ambiguously called a unit matrix, of size n is the n × n square matrix with ones on the main diagonal and zeros elsewhere. Multiplying by the identity matrix I doesn't change anything, just like multiplying a number by 1 doesn't change anything. This property is why I and 1 are each called the "multiplicative identity". But while there is only one "multiplicative identity" for regular numbers (namely the number 1), there are lots of different identity matrices.

transpose matrix

In linear algebra, the transpose of a matrix A is another matrix AT (also written A′, Atr, tA or At) created by any one of the following equivalent actions: reflect A over its main diagonal (which runs from top-left to bottom-right) to obtain AT write the rows of A as the columns of AT write the columns of A as the rows of AT Formally, the i th row, j th column element of AT is the j th row, i th column element of A: {\displaystyle [\mathbf {A} ^{\mathrm {T} }]_{ij}=[\mathbf {A} ]_{ji}} [\mathbf {A} ^{\mathrm {T} }]_{ij}=[\mathbf {A} ]_{ji} If A is an m × n matrix then AT is an n × m matrix.

higher order functions

In mathematics and computer science, a higher-order function (also functional, functional form or functor) is a function that does at least one of the following: takes one or more functions as arguments (i.e., procedural parameters), returns a function as its result.

Convex functions?

In mathematics, a real-valued function defined on an interval is called convex (or convex downward or concave upward) if the line segment between any two points on the graph of the function lies above or on the graph, in a Euclidean space (or more generally a vector space) of at least two dimensions. Equivalently, a function is convex if its epigraph (the set of points on or above the graph of the function) is a convex set. Well-known examples of convex functions include the quadratic function {\displaystyle x^{2}} x^{2} and the exponential function {\displaystyle e^{x}} e^{x} for any real number x. Convex functions play an important role in many areas of mathematics. They are especially important in the study of optimization problems where they are distinguished by a number of convenient properties. For instance, a (strictly) convex function on an open set has no more than one minimum.

What is differential calculus?

In mathematics, differential calculus is a subfield of calculus concerned with the study of the rates at which quantities change. It is one of the two traditional divisions of calculus, the other being integral calculus. The primary objects of study in differential calculus are the derivative of a function, related notions such as the differential, and their applications. The derivative of a function at a chosen input value describes the rate of change of the function near that input value. The process of finding a derivative is called differentiation. Geometrically, the derivative at a point is the slope of the tangent line to the graph of the function at that point, provided that the derivative exists and is defined at that point. For a real-valued function of a single real variable, the derivative of a function at a point generally determines the best linear approximation to the function at that point.

What are first order methods in numerical analysis?

In numerical analysis, methods that have at most linear local error are called first order methods. They are frequently based on finite differences, a local linear approximation.

Define Lazy Evaluation

What is normalization?

In statistics and applications of statistics, normalization can have a range of meanings.[1] In the simplest cases, normalization of ratings means adjusting values measured on different scales to a notionally common scale, often prior to averaging. In more complicated cases, normalization may refer to more sophisticated adjustments where the intention is to bring the entire probability distributions of adjusted values into alignment. In the case of normalization of scores in educational assessment, there may be an intention to align distributions to a normal distribution. A different approach to normalization of probability distributions is quantile normalization, where the quantiles of the different measures are brought into alignment.

What is overfitting?

In statistics and machine learning, one of the most common tasks is to fit a "model" to a set of training data, so as to be able to make reliable predictions on general untrained data. In overfitting, a statistical model describes random error or noise instead of the underlying relationship. Overfitting occurs when a model is excessively complex, such as having too many parameters relative to the number of observations. A model that has been overfit has poor predictive performance, as it overreacts to minor fluctuations in the training data. how to avoid overfitting? cross-validation, regularization, early stopping, pruning, Bayesian priors on parameters or model comparison and more!

What's different about ES6 and Anonymous Function Expressions?

In the case of the anonymous function expression, the function is anonymous — literally, it has no name. However, in ES6, they do!!! Well, most of the time. (As of ES6, though, a lot of "anonymous" function expressions create functions with names, and this was predated by various modern JavaScript engines being quite smart about inferring names from context. In ES6, your anonymous function expression results in a function with the name boo. This is strewn throughout the spec rather than being defined in one place with a bunch of rules.)

Socket types

LGA 775, Socket M, Socket 441, Socket AM2/AM2+/AM3/AM3+, LGA 1366 , LGA 1156

Failsafe

Loads Linux with a minimal set of drivers and services. Similar to Safe MOde on a Windows System.

List the Chrome DevTools Storage Items

Local Storage, Session Storage, IndexedDB, WebSQL, Cookies

Array.prototype.pop()

MUTATOR method Removes the last element from an array and returns that element.

Array.prototype.sort()

MUTATOR method Sorts the elements of an array in place and returns the array.

Match any character except newline (For example, /.n/ matches 'an' and 'on' in "nay, an apple is on the tree", but not 'nay'. Take note that that means anything that is NOT optional is mandatory. 'nay' is not matched because it doesnt have the specific order of a single character and then the 'n' character.)

^ (Anchor)

Match beginning of input (Matches beginning of input. If the multiline flag is set to true, also matches immediately after a line break character. For example, /^A/ does not match the 'A' in "an A", but does match the 'A' in "An E". The '^' has a different meaning when it appears as the first character in a character set pattern. See complemented character sets for details and an example.)

MTBF

Mean Time Between Fialure, how long a drive will last before it fails. ALL hard drives will fail it's a matter of when.

Sticky Bit

When the Sticky Bit is assigned to a directory users can only delete files within the directory for which they are the owner of the file or the directory itself. This negates the effect of having the wirte permission to a directory, which could allow a user to delete files in a directory that he or she doesn't own.

Port 110

POP3

When were React and ReactDOM split?

React and ReactDOM were only recently split into two different libraries. Prior to v0.14, all ReactDOM functionality was part of React. This may be a source of confusion, since any slightly dated documentation won't mention the React / ReactDOM distinction. As the name implies, ReactDOM is the glue between React and the DOM. Often, you will only use it for one single thing: mounting with ReactDOM.render(). Another useful feature of ReactDOM is ReactDOM.findDOMNode() which you can use to gain direct access to a DOM element. (Something you should use sparingly in React apps, but it can be necessary.) If your app is "isomorphic", you would also use ReactDOM.renderToString() in your back-end code. For everything else, there's React. You use React to define and create your elements, for lifecycle hooks, etc. i.e. the guts of a React application. The reason React and ReactDOM were split into two libraries was due to the arrival of React Native. React contains functionality utilised in web and mobile apps. ReactDOM functionality is utilised only in web apps. [UPDATE: Upon further research, it's clear my ignorance of React Native is showing. Having the React package common to both web and mobile appears to be more of an aspiration than a reality right now. React Native is at present an entirely different package.] See the blog post announcing the v0.14 release: https://facebook.github.io/react/blog/2015/10/07/react-v0.14.html

If You Don't Do This, You are Headed for Trouble

Remember that a person's name is to that person the sweetest and most important sound in any language.

Node EventEmitter class

The EventEmitter class is used as a construct to help us build the publish/subscribe pattern of the event model of writing async code. the subscriber: emitter.on(event, listener); the publisher: emitter.emit(event, [args]);

Node.appendChild()

The Node.appendChild() method adds a node to the end of the list of children of a specified parent node. If the given child is a reference to an existing node in the document, appendChild() moves it from its current position to the new position (there is no requirement to remove the node from its parent node before appending it to some other node). Returns the appended child. var addCourseToDom = function addCourseToDom(course){ var li = document.createElement("li"); var text = document.createTextNode(course.title); li.appendChild(text); var placeToAdd = document.getElementById("courses"); placeToAdd.appendChild(li); return "added " + li; }

The NodeJS Docs have stability indexes. What does this mean?

The Node.js API is still somewhat changing, and as it matures, certain parts are more reliable than others. Some are so proven, and so relied upon, that they are unlikely to ever change at all. Others are brand new and experimental, or known to be hazardous and in the process of being redesigned. Stability 0 - 3. Only use features from Stability 2-3 if you really want to have consistent and compatible code

Object.create

The Object.create() method creates a new object with the specified prototype object and properties. Object.create(proto[, propertiesObject]) // Example where we create an object with a couple of sample properties. // (Note that the second parameter maps keys to *property descriptors*.) o = Object.create(Object.prototype, { // foo is a regular 'value property' foo: { writable: true, configurable: true, value: 'hello' }, // bar is a getter-and-setter (accessor) property bar: { configurable: false, get: function() { return 10; }, set: function(value) { console.log('Setting `o.bar` to', value); } /* with ES5 Accessors our code can look like this get function() { return 10; }, set function(value) { console.log('setting `o.bar` to', value); } */ } });

Object.freeze()

The Object.freeze() method freezes an object: that is, prevents new properties from being added to it; prevents existing properties from being removed; and prevents existing properties, or their enumerability, configurability, or writability, from being changed. In essence the object is made effectively immutable. The method returns the object being frozen.

OPENVas

The Open Vulnerability Assessment System, or OpenVAS, is a free network security scanner licenced under the GNU General Public Licence. It's available in several Linix packages or as a downloadable Virtual Appliance for testing and evaluation. While the scanner doesn't work on Windows, Windows clients are available. The biggest chunk of OpenVAS is the security scanner, which only runs in Linux. Geier says this is the part that does the actual scanning and receives a feed, updated daily, of more than 33,000 Network Vulnerability Tests (NVT). The OpenVAS Manager controls the scanner and provides the intelligence. OpenVAS isn't the quickest and easiest tool to install and use, but it has one of the best feature sets of any free security scanner, Geier says. The drawback: its main component does require Linux. Read more: http://www.itworldcanada.com/post/six-free-network-vulnerability-scanners#ixzz3MCbzUXy3 or visit http://www.itworldcanada.com for more Canadian IT News

String.prototype[@@iterator]()

The [@@iterator]() method returns a new Iterator object that iterates over the code points of a String value, returning each code point as a String value. string[Symbol.iterator]

What happens if you initialize a parameter at a local minimum and attempt to use gradient descent on it?

The derivative turns out to be zero because the tangent is a flat line meaning that regardless of alpha it is multiplied by zero, indicating no change.

ES6: export

The export statement is used to export functions, objects or primitives from a given file (or module). export { name1, name2, ..., nameN }; export { variable1 as name1, variable2 as name2, ..., nameN }; export let name1, name2, ..., nameN; // also var export let name1 = ..., name2 = ..., ..., nameN; // also var, const export default expression; export default function (...) { ... } // also class, function* export default function name1(...) { ... } // also class, function* export { name1 as default, ... }; export * from ...; export { name1, name2, ..., nameN } from ...; export { import1 as name1, import2 as name2, ..., nameN } from ...;

What is [[Prototype]]?

The mechanism by which objects can point to their successors. Basically a reference to another object. Written in the spec, not public

String.prototype.search()

The search() method executes a search for a match between a regular expression and this String object. str.search(regexp)

String.prototype.trim()

The trim() method removes whitespace from both ends of a string. Whitespace in this context is all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator characters (LF, CR, etc.). str.trim()

Tsconfig.json?

The tsconfig.json file specifies the root files and the compiler options required to compile the project.

String.prototype.valueOf()

The valueOf() method returns the primitive value of a String object. str.valueOf() The valueOf() method of String returns the primitive value of a String object as a string data type. This value is equivalent to String.prototype.toString(). This method is usually called internally by JavaScript and not explicitly in code.

What does this return? function myFunction() { return this; } myFunction();

This example returns the window object as the value of this: // Will return the window object [object Window]

SGID

When a user runs an executable file with SGID set, the user temproraily becomes a member of the file's owning group. When a user creates a file in a directory that has SGID set, the file's owner is set to the user's account (as per normal). HOwever the owning group assigned to the new file is set to the owning group of the parent directory.

Does resetting the prototype constructor in a subclass matter?

Yes and no. In ES5 and earlier, JavaScript itself didn't use constructor for anything. It defined that the default object on a function's prototype property would have it and that it would refer back to the function, and that was it. Nothing else in the specification referred to it at all. That changed in ES2015 (ES6), which started using it in relation to inheritance hierarchies. For instance, Promise#then uses the constructor property of the promise you call it on (via SpeciesConstructor) when building the new promise to return. It's also involved in subtyping arrays. Note that in the places the ES2015 spec uses it, it's set automatically for you (you can't subclass Promise or arrays except via class, and class handles it for you). Outside of the language itself, sometimes people would use it when trying to build generic "clone" functions or just generally when they wanted to refer to what they believed would be the object's constructor function. My experience is that using it is rare, but sometimes people do use it. It's there by default, you only need to put it back when you replace the object on a function's prototype property: Student.prototype = Object.create(Person.prototype); If you don't do this: Student.prototype.constructor = Student; ...then Student.prototype.constructor inherits from Person.prototype which (presumably) has constructor = Person. So it's misleading. It's okay if nothing in your code (or library code you use) uses it. I've always ensured it was correctly wired up. Of course, with ES2015 (aka ES6)'s class keyword, most of the time we would have used it, we don't have to anymore, because it's handled for us when we do class Student extends Person { }

[1,2,3,4,5].copyWithin(0, 3);

[4, 5, 3, 4, 5]

[1,2,3,4,5].fill(4);

[4,4,4,4,4]

What is the value of arr1 after arr1.filter(num => num > 5); where let arr1 = [4,7,9,1];

[4,7,9,1]; (array that is filtered is unchanged)

What is the return value of arr1.filter(num => num > 5); where let arr1 = [4,7,9,1];

[7,9];

function outside(x) { function inside(y) { return x + y; } return inside; } fn_inside = outside(3); Value of fn_inside?

a function that adds 3 to whatever you give it.

Clustering

a method of unsupervised learning - a good way of discovering unknown relationships in datasets. Cluster analysis or clustering is the task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense or another) to each other than to those in other groups (clusters). It is a main task of exploratory data mining, and a common technique for statistical data analysis, used in many fields, including machine learning, pattern recognition, image analysis, information retrieval, bioinformatics, data compression, and computer graphics. Cluster analysis itself is not one specific algorithm, but the general task to be solved. It can be achieved by various algorithms that differ significantly in their notion of what constitutes a cluster and how to efficiently find them. Popular notions of clusters include groups with small distances among the cluster members, dense areas of the data space, intervals or particular statistical distributions. Clustering can therefore be formulated as a multi-objective optimization problem. The appropriate clustering algorithm and parameter settings (including values such as the distance function to use, a density threshold or the number of expected clusters) depend on the individual data set and intended use of the results. Cluster analysis as such is not an automatic task, but an iterative process of knowledge discovery or interactive multi-objective optimization that involves trial and failure. It is often necessary to modify data preprocessing and model parameters until the result achieves the desired properties.

unshift()

adds given value to the front of an array array will get bigger

: groupadd

adds groups to linux system . - groupadd options groupname -- groupadd dbusers . -g -p -r

First sisterhood?

alpha Delta Pi

VI: CTRL-G

displays status line at bottom of interaface that includes name of file,s tates of file, number of lines, etc

Chrome $() equivalent

document.querySelector(); (Returns the first matching Element node within the node's subtree. If no matching node is found, null is returned.) (Returns the first element that matches the specified CSS selector. It is a shortcut for document.querySelector )

eth0

eth0 is the Ethernet network interface installed in the system

AJS: Two keywords that cheat lexical scope?

eval, with

What are Node's built in modules?

exports._builtinLibs = ['assert', 'buffer', 'child_process', 'cluster', 'crypto', 'dgram', 'dns', 'events', 'fs', 'http', 'https', 'net', 'os', 'path', 'punycode', 'querystring', 'readline', 'repl', 'string_decoder', 'tls', 'tty', 'url', 'util', 'vm', 'zlib'];

What does Incognito Mode do?

fresh cache, no cookies, no history (It essentially sets the cache path to a temporary folder. Cookies are still used, but everything starts "fresh" when the incognito window is launched. This applies all storage, including Cookies, Local Storage, Web SQL, IndexedDB, cache, etc. Of course Chrome also leaves pages out of the browser's history.)

Brotherhood is a feeling that comes...

from the experiences shared with close friends. It transecends typical friendship, becoming a familial relationship.

Linux path difference

full path or ./, case sensitive, etc.

Explain Function.prototype.apply()

fun.apply(thisArg, [argsArray]) thisArg The value of this provided for the call to fun. Note that this may not be the actual value seen by the method: if the method is a function in non-strict mode code, null and undefined will be replaced with the global object, and primitive values will be boxed. argsArray An array-like object, specifying the arguments with which fun should be called, or null or undefined if no arguments should be provided to the function. Starting with ECMAScript 5 these arguments can be a generic array-like object instead of an array. See below for browser compatibility information.

.call() what are the parameters?

fun.call(thisArg[, arg1[, arg2[, ...]]]) (thisArg The value of this provided for the call to fun. Note that this may not be the actual value seen by the method: if the method is a function in non-strict mode code, null and undefined will be replaced with the global object and primitive values will be converted to objects. arg1, arg2, ... Arguments for the object. )

AJS: Why use .call(this) for IIFE's?

Write a function that adds from two invocations. add(3)(4) // 7 add(12)(20) // 32

function add(a){ return function(b){ a + b }; }

Celebrities, Crockford, Closures, Pass-by-Reference

Find the odd int - Given an array, find the int that appears an odd number of times. There will always be only one integer that appears an odd number of times.

Write a function length that finds the length of a linked list with no new objects created.

function length (head) { let count = 0; while (head) { count++; head = head.next; } return count; }

two members of phi delta theta getting distinction from women

george banta sr,., franklin-indiana 1876- in 1879 georgre banta initiated to help DG expansion effort

Get rid of daemons on server

get rid of unnecssary daemons that consume memory and may open security holes

g flag

global search ( The "g" flag indicates that the regular expression should be tested against all possible matches in a string.)

:bnext (or :bn)

go to next buffer

:bprev (of :bp)

go to previous buffer

Mixing up Backups

good idea because certain backups take too long to run. whereas if you mix you can get the best bang for your buck. -- Thinka botu when to run certain backups. Maybe running a fullbackup once a week when system load is light on Friday night and then incremental backups on the toher six days.

jump backward by words (punctuation considered words)

mkdir

make directory

: ifconfig

manages network boards installed in system, display or modify network board configuration parameters

is myFunction() and window.myFunction() different?

myFunction() and window.myFunction() is the same function:

// create an object var myObject = {}; // create a method on our object myObject.someMethod = function () { console.log(this); }; // call our method myObject.someMethod(); what does myObject.someMethod(); put out?

myObject

What is the owner of the fullName function?

myObject is the owner of the function.

What is a zero matrix?

n mathematics, particularly linear algebra, a zero matrix or null matrix is a matrix with all its entries being zero. Acts as the additive identity.

$ENV

name of file bash read to configure its environment

Creative Commons

negotiate directly and individually with copyright owner

subnet mask

network vs node address -- subnets determine how much of an address is used for the network and how much for the node. 255.0.0.0 - class A - network vs node

Hyperthreading CPUs

once popular have been replaced by multicore CPUs. -- one single processor can run more than one process

React.createClass accepts?

one argument, an object of which the only property required is the render function

when can napkins be tucked in

only if riding on a plane

open (append) blank line below current line (no need to press return)

OSI - Open Source Initiative

open soruce as a viable alternative

ALT + FX

open up a new shell session

PICO: CTRL-W

search for text in file

How are matrices denoted? Columns then rows or rows then columns?

rows x columns

var fn = function () { // the `||` symbol here is being used to set a default value for innerCounter. If innerCounter already contains a truthy value, then the value in that variable will be unchanged. If it is falsey however (such as if it were completely uninitialized), then this line will set it to the default value of 10. var innerCounter = innerCounter || 10; innerCounter = innerCounter + 1; ACTUAL = innerCounter; }; fn(); expect(ACTUAL === '11').to.be.true; fn(); expect(ACTUAL === '10').to.be.true; //whats wrong here?

second value is 11 because scope is recreated

&& || AND OR

slightly different from C programming the && is used the second command is executed only if first command runs and exited correctly. for cmd1 || cmd2 the second command is excecuted only if the first command runs and exits abnormally with a nonzero exit status.

Sockets

sockets are similar to FIFOs in that they are used to transfer information between processes. UNlike FiFos, however, sockets can move data bidirectionally

/etc/resolv.conf

specifies the DNS server and domain suffix used by the system

: dhclient eth0

specify that your eth0 interface gets IP address dynamically from DHCP

: split

splits an input file into a series of files w/o altering the original input file.

ES6: The spread operator is also called...

spread, rest, gather

sshd

ssh daemon that allows remote access to shell prompt

FIFO

stands for first in first out. move data from one software process on the system to another.

y flag

sticky search The sticky property reflects whether or not the search is sticky (searches in strings only from the index indicated by the lastIndex property of this regular expression). sticky is a read-only property of an individual regular expression object.

: traceroute

utility traces route a packet must traverse through routers to arrivae at its destination: syntax traceroute destination

Write up a quick display of the module pattern with a function called Module, privateProperty, privateMethod, publicProperty, publicMethod, and privilegedMethod

Create a property firstName within a class Person

var Person = function (firstName) { this.firstName = firstName; }; //instantiation: var person1 = new Person('Alice');

Create a method sayHello on a class Person using the prototype design pattern

var Person = function (firstName) { this.firstName = firstName; }; Person.prototype.sayHello = function() { console.log("Hello, I'm " + this.firstName); };

class Student { fullName: string; constructor(public firstName, public middleInitial, public lastName) { this.fullName = firstName + " " + middleInitial + " " + lastName; } } interface Person { firstName: string; lastName: string; } function greeter(person : Person) { return "Hello, " + person.firstName + " " + person.lastName; } var user = new Student("Jane", "M.", "User"); document.body.innerHTML = greeter(user); Typescript -> ES5 compiles to....?

Document.createElement()

var element = document.createElement(tagName); *element* is the created Element object. *tagName* is a string that specifies the type of element to be created. The nodeName of the created element is initialized with the value of tagName. Don't use qualified names (like "html:a") with this method.

syntax of testing if the value of this belong to the global object

var myObject = { firstName:"John", lastName: "Doe", fullName: function () { return this; } } myObject.fullName(); // Will return [object Object] (the owner object)

parameter

var nameImprover = function (name, adj) { return 'Col' + name + 'Mc' + adj + pants; }

Use Math.max with apply to find the maximum value of [1,2,3,4,5]; and do it without it apply as well.

var numbers = [1,2,3,4,5]; var max = Math.max.apply(null, numbers); var max2 = Math.max(1,2,3,4,5);

<this> explained in rohit khan

How do we create an instance or object of a class named Person?

var person1 = new Person();

What are the two ways to define regular expressions in Javascript? (Code for a string with an 'a', one or more 'b's and a 'c')

var re /ab+c/; var re = new RegExp("ab+c"); (1. Using a literal, which is a pattern enclosed in slashes. var re = /ab+c/. 2. Calling the constructor function of the RegExp object. var re = new RegExp("ab+c");)

Recursive Function Recipe

var recurse = function() { if (){ //basecase } else { //recursive case recurse(); } return;

Rewrite the following async code that utilizes callbacks to using events getThem(param, function(err, items) { //check for err //operate on array of items }

local variables

varaibles defined inside a pair of curly braces and exist only while executing the part of the program within those braces.

: jobs

view current jobs running -- which ones are background and which ones arent? the first value [1] is the background job ID the second value is the PID of the process --

: | more

view pages one at a time -- pausing display.

Burrows-Wheeler Compression Algorithm

what bzip2 uses

Lempel-Ziv Copmression Algorithm

what gzip utility uses

: type

will return type of a command as one of following shellbuiltin hashed (external command) aias of another cmd a function -a flag causes type to return all isntances of the specified command in the file system.

configuring openssh

~/ssh/ssh_config, /etc/ssh/ssh_config allowusers restricts login to the ssh server to only users listed, denyusers prevents users listed from loggin in through ssh server, hostkey specifies which private host key file should be used by ssh. listenaddress if the host where sshd is running has multiple ip addresses assigned oyu can restrict sshfd to only listening on specifc addresses using this param. permitrootlogin specifies whether you can authenticate through ssh server as root, port, specifies port on which sshd will listen for ssh requests , protocol specifies which version of ssh to use , stricthostkeychecking -- ssh server sensds ssh client its public key when yu initiate an ssh connection. by default, the first time you connect to a given ssh server you are prompted on the client end to accept the server's public key. user

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