ProfMesser: Basic Linux Commands

what to type if you wanted to change directory to the var/log directory:

"cd /var/log"

command to get all of the information for the "eth0" adapter card:

"ifconfig eth0"

If you want to connect to an SSID

"iwconfig eth0 (name of adapter) essid(specify you want to connect to an essid) studio-wireless(name of the ssid)"

command to create a new directory called "notes":

"mkdir notes"

command to rename a file "first.txt" to "second.txt"

"mv first.txt second.txt"

command to view every process for every user:

"ps -e | more"

command to view user processes

"ps"

directories can be removed with rm this way:

"rm -r"

Command to change the owner of a file "script.sh" to "professor":

"sudo chown professor script.sh"

command to restart the computer after 3 minutes

"sudo shutdown -r 3"

syntax for starting the visual editor

"vi FILENAME"

command to start the visual editor for file "script.sh"

"vi script.sh"

chown (2):

- change file owner and group - sudo chown [OWNER:GROUP] file

chmod: change mode of a file system object (3):

- r=read, w=write, x=execute, - can also use octal notation, - set for the file owner (u), the group (g), others(o), or all(a)

iwconfig (4):

- view or change wireless network configuration - essid, frequency / channel, mode, rate, etc. - requires some knowledge of the wireless network - iwconfig eth0 essid studio-wireless

apt-get (4):

-Advanced Packaging Tool - Handles the management of application packages - Install, update, remove - sudo apt-get install wireshark

su (3):

-Become super user - Or change to a different user, - You continue to be that user until you type "exit"

passwd (2):

-Change a user account password - Yours or another - passwd [username]

cd (3):

-Change current directory - nearly identical to Windows command but uses forward slashes instead - cd <directory>

sudo (3):

-Execute a command as the super user, - Or as a different user ID, - Only that command executes as the super user

grep (2):

-Find text in a file, - grep PATTERN [FILE]

ls:

-List directory contents (similar to dir in Windows), - Lists files, directories, - For long output, pipe through more: "ls -l | more"

pwd (3):

-Print Working Directory, - Displays the current working directory path, - Useful when changing directories often

ps:

-View the current processes - and the process ID (PID) - similar to the Windows Task Manager - View user processes (ps) - view all processes for all users (ps -e | more)

cp (2):

-duplicate files or directories, - cp SOURCE DEST

apt-get: Advanced Packaging Tool:

-easily find packages and install them into your Linux distribution - handles the management of application packages

mkdir (2):

-make a directory, - mkdir DIRECTORY

rm (2):

-remove files or directories, - does not remove directories by default. Directories must be removed with "rm -r"

mv (2):

-rename a file, - move a file

"apt" in apt-get stands for

Advanced Packaging Tool

Commands looked at in this video are similar in both

Linux and Mac OS

Command to shutdown or start a Linux device

SHUTDOWN

permissions of file separated into:

User, Group, Other. rwx(user)rwx(group)rwx(other)

popular editor that's found in almost every Linux distribution

Vi

The grep command is

a search function that allows you to look for some text that may be located in one or more files.

command: chmod a-w first.txt would mean that

all users would not be able to write to first.txt

One common command to install, update, or remove applications from the command line is

apt-get

command that allows you to change the directory

cd

cd command allows you to

change directory

command to change the file permissions

chmod

command to set permissions of file: script.sh to user: read, group: write, other: execute:

chmod 421 script.sh

command to set permissions of file: script.sh to user: read write execute, group: read write execute: other: read write execute.

chmod 777 script.sh

chmod syntax:

chmod mode FILE

command to copy a file

cp

cp syntax:

cp SOURCE_NAME _DESTINATION_NAME

command to copy the file "first.txt" and rename the copied file "second.txt":

cp first.txt second.txt

ls: If you were in Windows you would be using the __ command.

dir

some commands require

elevated rights

rmdir can remove

empty directories

chmod: permissions denoted by 1

execute only

what the ps command does

lists out all of the current processes and process IDs

How to get long output with ls command

ls -l

what the command "sudo chown professor script.sh" does

makes the owner of script.sh "professor"

man command stands for

manual

command to create directory

mkdir

mkdir syntax

mkdir DIRECTORY

what mv command does

move a file, rename a file.

command to move a file

mv

command to rename a file

mv

In Linux, every file is

owned by a particular user, and there are also rights and permissions associated with a group that may be associated with that file.

command to change the password for your account

passwd

ls: for long output ...

pipe through more: "ls -l | more". Use "q" or Ctrl - c to exit

Command to cancel a shutdown or restart

press "Ctrl -c"

Once you're inside vi, you can insert text by:

pressing the "i" key, and then specifying what text you'd like to have input.when you're finished with the input process, you will usually press Escape to get out of input mode.

command to find out what directory currently in

pwd

chmod: permissions denoted by 5

read and execute

chmod: permissions denoted by 6

read and write

chmod: permissions denoted by 4

read only

chmod: permissions denoted by 7:

read, write, and execute

chmod: usually changing the mode to be either:

read, write, or execute

rm stands for

remove files or directoires

command to remove file with filename: "temp-1.doc":

rm temp-1.doc

Directories must be empty to be removed with

rmdir

shutdown: you usually are going to...

run this as a superuser

apt-get command to install Wireshark

sudo apt-get install wireshark

chown syntax:

sudo chown [OWNER:GROUP] file

Command to wait 2 minutes then shutdown the computer

sudo shutdown 2

cd similar to cd in Windows. Difference is...

that in Linux we are going to use forward slashes instead of backslashes

You usually access the Linux command line by using

the Terminal, XTerm, or some similar terminal program.

ps is similar to

the Windows Task Manager

The cd command in linux is very similar to

the cd command in Windows that allows you to change directory.

Whenever you're working at the command line with these files and you need to change these rights and permissions...

the chmod will be the utility that you use to do that.

chmod: change mode of a file system object (3): set for...

the file owner (u), the group (g), others(o), or all(a)

To make a directory in Linux, we use

the mkdir command

command: chmod u+x first.txt would mean that

the owner of script.sh can execute the file

similar to the Windows Task Manager

the ps command

If you don't know what directory you're currently in...

use the "pwd" command. Stands for print working directory

chmod: permissions denoted by 744:

user: read, write, and execute, group: read only, other: read only

ifconfig:

view or configure a network interface and IP configuration

what command "sudo shutdown 2" does

waits 2 minutes then shuts down the computer

chown: if we want to change the ownership of a file...

we may want to look at who owns the file currently, If we use the ls -l command, we can see that script.sh <example> is owned by backup and is part of the group "staff."

To be able to change the file owner or the group owner...

we would use the chown command, and usually you have to use elevated rights

To use grep...

we would use the grep command, we would specify a pattern, and then specify what files we wanted to look inside: - "grep PATTERN [FILE]" -example: "grep failed auth.log"

To delete a file from a filesystem...

we would use the rm command

chmod: permissions denoted by 3

write and execute

chmod: permissions denoted by 2

write only

if you have a number of tasks that you need to execute as the superuser,

you can start this mode by simply typing in "su"

If you want to see the IP address configurations of any of your network adapters,

you can use ifconfig

If you'd like to execute just one command in the superuser mode,

you can use the "sudo" command.

If you want to view or change any of the wireless configuration settings of a wireless adapter inside Linux...

you want to use the iwconfig command