Chapter 18: macOS, Linux, and Scripting

Bash shell

The default shell used by the terminal for many distributions of Linux.

iwconfig

A Linux and macOS command similar to ifconfig that applies only to wireless networks. Use it to display information about a wireless interface and configure a wireless adapter.

passwd

A Linux and macOS command to change a password. A superuser can change the password for another user.

chmod

A Linux and macOS command to change modes (or permissions) for a file or directory.

chown

A Linux and macOS command to change the owner of a file or directory.

sudo

A Linux and macOS command to execute another command as a superuser when logged in as a normal user with an account that has the right to use root commands.

apt-get

A Linux and macOS command to install and remove software packages and install OS updates.

su (substitute user or switch user)

A Linux and macOS command to open a new terminal shell for a different user account.

grep

A Linux and macOS command to search for and display a specific pattern of characters in a file or multiple files.

kill

A Linux and macOS command used to forcefully end or kill a process.

kernel panic

A Linux or macOS error from which it cannot recover, similar to a blue screen of death in Windows.

dock

A bar at the bottom of the macOS desktop where application icons can be placed for easy access.

package

A collection of files needed to install software.

multiple desktops

A feature of Mission Control in macOS, where several desktop screens, each with its own collection of open windows, are available to the user.

Remote Disc

A feature of macOS that gives other computers on the network access to the Mac's optical drive.

First Aid

A macOS tool in Disk Utility that scans a hard drive or other storage device for file system errors and repairs them.

swap partition

A partition on a Linux hard drive used to hold virtual memory.

JavaScript

A scripting language normally used to create scripts for webpages; the scripts are embedded in an HTML file to build an interactive webpage in a browser.

VBScript

A scripting language that creates scripts modeled after the more complex Visual Basic programming language. These kinds of scripts have a .vbs file extension.

basic loop

A scripting or programming technique to execute the same group of commands multiple times until a condition is met.

dynamic type checking

A technique in scripting and programming whereby each command line is checked by the command interpreter software to verify that the command can be executed.

NetBoot

A technology that allows a Mac to boot from the network and then install macOS on the machine from a clone DMG file stored on a deployment server.

Telnet

A terminal emulation protocol that allows users at one site to simulate a session on a remote host. It uses port 23.

batch file

A text file containing a series of OS commands. Autoexec.bat is an example.

shell script

A text file of Linux commands that can be executed as a batch.

PowerShell script

A text file of PowerShell commands that can be executed as a batch.

Python script

A text file of commands that use the Python scripting language and that can be executed as a batch.

script

A text file that contains a list of commands that can be interpreted and executed by the OS.

superuser

A user who is logged in to the root account.

Boot Camp

A utility in macOS that allows you to install and run Windows on a Mac computer.

Linux

An OS based on UNIX that was created by Linus Torvalds of Finland. Basic versions of this OS are open source, and all the underlying programming instructions are freely distributed.

secondary-click

An action in macOS that is similar to a right-click in Windows. By default, the action is a tap with two fingers on the Mac trackpad.

gestures

An action performed on the Mac trackpad using one or more fingers.

PowerShell ISE

An environment used to create, edit, and test PowerShell scripts.

ext3

An older Linux file system. It was the first to support journaling, which is a technique that tracks and stores changes to the hard drive and helps prevent file system corruption.

HFS+ (Hierarchical File System Plus)

An older macOS file system for macOS 10.12 and earlier versions that uses a proprietary Apple partitioning system. Also called the Mac OS Extended file system.

macOS

Apple's operating system

Windows as a service

Beginning with Windows 10, the Microsoft strategy to deploy Windows and then provide ongoing, incremental updates to service the OS with no end-of-life limitation. In comparison, earlier versions of Windows had more discrete and significant updates, and end-of-life limitations required you to eventually upgrade to a new version of Windows.

environmental variable

Data the OS makes available to a script or program for use during its execution. For example, the TEMP variable tells a script where it can store its temporary files. Also called a system variable.

vi editor

In Linux and macOS, a text editor that works in command mode (to enter commands) or in insert mode (to edit text).

clone

In Linux and macOS, an image of the entire partition on which the OS is installed.

root account

In Linux and macOS, the account that gives the user access to all the functions of the OS; the principal user account.

dd

In Linux and macOS, the command to copy and convert files, directories, partitions, and entire DVDs or hard drives. You must be logged in as a superuser to use the command.

terminal

In Linux and macOS, the command-line interface.

Live CD

In Linux, a CD, DVD, or flash drive that can boot up a live version of Linux, complete with Internet access and all the tools you normally have available in a hard drive installation of Linux. The OS does not need to be installed on the hard drive.

Live USB

In Linux, a USB flash drive that runs a live version of a Linux. The operating system does not need to be installed on the hard drive. Also see Live CD.

forced kill

In Linux, to abruptly end an app without allowing the app to go through its close process.

Space

In mac OS, one desktop screen when multiple desktops are open to users.

snapshots

In macOS, a backup created by Time Machine.

Time Machine

In macOS, a built-in backup utility that can be configured to automatically back up user-created data, applications, and system files to an external hard drive attached either directly to the computer or the local network.

Keychain

In macOS, a built-in password manager utility.

DMG file

In macOS, a disk image file similar to WIM or ISO files in Windows.

login items

In macOS, a program that automatically launches after a user logs in. Login items are managed in the Users & Groups utility in System Preferences.

Mission Control

In macOS, a utility and screen that gives an overview of all open windows and thumbnails of the Dashboard and desktops.

System Preferences

In macOS, a utility to customize the macOS interface; it is available on the Apple menu.

Screen Sharing

In macOS, a utility to remotely view and control a Mac; it is similar to Remote Desktop in Windows.

startup items

In macOS, programs that automatically launch at startup. Apple discourages the use of these types of programs because they slow down startup and because they may be malware.

APFS (Apple File System)

In macOS, the default file system for SSDs; it can also be used for magnetic hard drives. It uses the GUID partitioning system.

startup disk

In macOS, the entire volume on which macOS is installed.

swapfile

In macOS, the file used to hold virtual memory, similar to pagefile.sys in Windows.

Apple menu

In macOS, the menu that appears when the user clicks the Apple icon in the upper left corner of the screen.

Spotlight

In macOS, the search app that can be configured to search the local computer, Wikipedia, iTunes, the Maps app, the web, and more.

force quit

In macOS, to abruptly end an app without allowing the app to go through its close process.

strings

In scripting and programming, a type of data that can contain any character but cannot be used for calculations.

integers

In scripting and programming, a type of data that is a whole number.

ifconfig

Linux command for finding out a computer's IP address information

GRUB (GR and Unified Bootloader)

The current Linux boot loader, which can handle dual boots with another OS installed on the system.

ext4 (fourth extended file system)

The current Linux file system.

run-time environment

The environment provided by the operating system in which commands contained in a script file are interpreted and executed.

Finder

The macOS utility used to find and view applications, utilities, files, storage devices, and network resources available to macOS. It is similar to Windows File Explorer.

Launchpad

The macOS utility used to launch and uninstall applications.

variable

The name of one item of data used in a script or program.

comment syntax

The text in a script or program that tags a line as documentation so it is not interpreted as a command in the script or program.

SSH (Secure Shell)

This protocol uses encryption to make a secure connection as either client or server. You would use it to manage a multi-layer switch with a secure connection.