| Terminology | Definition |
|---|---|
| Devops | A Combination of software development and system operations, and refers to the practice of integrating one discipline with the other |
| DevSecOps | A Combination of software development, security operations, and systems operations, and refers to the practice of integrating each discipline with others. |
| Distribution (Distro) | A packaged version of Linux that includes the kernel, system tools, libraries, and software. |
| Kernel | The core of the Linux operating system that manages hardware and system resources. |
| CLI (Command Line Interface) | A text-based interface used to interact with the operating system by typing commands. |
| GUI (Graphical User Interface) | A visual interface that allows users to interact with the system using windows, icons, and menus. |
| Shell | A program that interprets and executes user commands (e.g., Bash, Zsh, PowerShell). |
| Bash (Bourne Again Shell) | The default command-line shell for most Linux distributions. |
| Option (Switch) | A modifier that changes how a command behaves (e.g., -l in ls -l). |
| Argument | The target or object a command operates on (e.g., a file or directory name). |
| Man Page | The built-in Linux manual that documents commands and configuration files. |
| Tab Completion | A shell feature that automatically completes command or file names. |
| Command History | A record of previously executed commands stored by the shell. |
| FHS (Filesystem Hierarchy Standard) | A standard that defines the directory structure and file locations in Linux. |
| Root Account | The superuser account with unrestricted access to the system. |
| sudo | A command that allows permitted users to run commands with elevated privileges. |
| su (Switch User) | A command used to change the current user, often to the root account. |
| Text Editor | A program used to modify configuration files (e.g., Vim, Nano). |
| Vim | A powerful modal text editor commonly used on Linux systems. |
| Nano | A simple, user-friendly command-line text editor. |
| Open Source | Software whose source code is publicly available and can be modified and redistributed. |
Linux is an Open Source Operating System, because of the fact that anyone can create their own there are thousands of different Distributions (Distros). Though Many of the Distributions trace back to one of two, either Red Hat Linux or Debian
Linux frequently uses the Command Line Interface(CLI), while administrators for other Operating systems commonly use a Graphical User interface.
- Speed - Usually quicker to execute a series of commands at the CLI
ip # Command
ip addr # Command + SubCommand
ls # Command
ls -l # Command + Argument
ls /var/log -l # Command + Option + Argument
history
1 ls
2 whoami
3 clear
!2
If you need assistance with the syntax of a command, you can use the manual for that command
man ls
ls -h
ls --help
whatis ls
Linux stores its configurations in text files. If you need to change system settings, you must edit these files. While there are many different ways to edit a text file in a GUI interface, there are many linux distributions that come without a GUI interface. Where you must edit the text file in the Command Line Interface.
vim /etc/pref_shell
i
SHELL=/bin/csh
export SHELL
esc
:wq
nano /etc/pref_shell
There are three types of accounts on Linux systems
Logging in with administrator access grants broad permissions and is not recommended. The Security best practice is to log in with a standard user and switch to an administrator account as needed with su.
su root # to switch from standard user to root
exit # to leave the root user
su -root # to switch from standard to root with root profile.