Linux Glossary

Plain English explanations of common Linux terms.

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Quick jump

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

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A

APT (Advanced Package Tool) Debian/Ubuntu's package manager. Think of it as your app store for the command line. Example: sudo apt install firefox

Arch A DIY Linux distribution. You build it piece by piece. Not for beginners, but you'll learn a lot.

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B

Bash The default command line shell in most Linux distros. Where you type commands. See also: Shell, Terminal

Binary A compiled program ready to run. Like an .exe file in Windows.

BTRFS A modern file system with snapshots and other features. Pronounced "Butter FS" or "Better FS".

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C

CLI (Command Line Interface) Text-based way to control your computer. Powerful once you learn it. Opposite of: GUI

Container A lightweight way to package and run applications with everything they need. Think shipping container for software. See: Docker Setup

Cron Schedule tasks to run automatically. Like "Run backup every night at 2 AM". Example: 0 2 * * * /home/user/backup.sh

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D

Daemon A background process that runs continuously. Like services in Windows. Example: sshd (SSH daemon), httpd (web server daemon)

Dependency Software that other software needs to work. Like needing flour to bake bread.

Distro (Distribution) A version/flavor of Linux. Ubuntu, Fedora, Mint are all distros. Think: Like ice cream flavors - same base, different toppings.

Docker Popular container platform. Run apps in isolated environments. Learn more: Docker Setup

Dotfile Hidden configuration file starting with a dot (.). Like .bashrc or .config.

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E

Environment Variable System-wide settings programs can read. Like PATH tells Linux where to find programs.

Ext4 The standard Linux file system. Reliable and mature.

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F

FOSS (Free and Open Source Software) Software that's free to use, modify, and share. The heart of Linux philosophy.

Fork When developers take existing code and create their own version. How many Linux projects start.

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G

Git Version control system. Track changes to code over time. Platform example: GitHub, GitLab, Codeberg

GNOME Popular desktop environment. Clean, modern interface.

GNU "GNU's Not Unix" - Free software project that provides many Linux tools.

GUI (Graphical User Interface) Point-and-click interface with windows and icons. Opposite of: CLI

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H

Home Directory Your personal folder. Usually /home/username. Shortcut: ~

Homelab Running server software at home for learning/personal use. See: Plex · Jitsi · Host (my server stack)

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I

Init System First process that starts when Linux boots. systemd is most common now.

ISO Disk image file. What you download to install Linux.

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J

Journal System logs in systemd. Check with journalctl.

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K

Kernel The core of Linux. Manages hardware and system resources. Think: The engine of your car

KDE Plasma Feature-rich desktop environment. Very customizable.

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L

LTS (Long Term Support) Versions supported for many years. Good for stability. Example: Ubuntu 22.04 LTS

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M

Man Page (Manual Page) Built-in documentation. Type man [command] for help. Example: man ls

Mount Make a drive/partition accessible. Like plugging in a USB stick. Learn more: Mount Commands

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N

Nginx Popular web server. Pronounced "Engine-X".

Node In networking: a device. In homelab: often means a server.

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O

Open Source Code anyone can see, modify, and share. See also: FOSS

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P

Package Software bundled for easy installation. Like an installer.

Package Manager Tool to install/remove/update software. APT, YUM, Pacman, etc.

PATH List of directories where Linux looks for programs.

Permission Who can read/write/execute files. The chmod command changes these.

PID (Process ID) Unique number for each running program.

Pipe ( | ) Send output from one command to another. Example: ls | grep document

Port Network endpoint. Like apartment numbers for network services. Example: Web servers use port 80 or 443

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R

Repository (Repo)

1. Where software packages live online
2. Git project containing code

Root

1. The superuser account (like Administrator in Windows)
2. The top directory /

Rolling Release Distro that continuously updates instead of having versions. See: Rolling vs Fixed

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S

Shell Command line interpreter. Bash, Zsh, Fish are different shells.

SSH (Secure Shell) Securely connect to remote computers. Example: ssh user@server.com

Sudo "Super User Do" - Run commands as administrator. Example: sudo apt update

Swap Disk space used as extra RAM when memory runs low.

Systemd Modern init system and service manager in most distros.

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T

Terminal Program that gives you command line access. Also called: Console, Command Line

Tiling Window Manager WM that automatically arranges windows without overlapping. Example: i3, dwm, Qtile. See: DWM Setup wiki

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U

UID (User ID) Unique number for each user account.

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V

Virtual Machine (VM) Computer running inside your computer. Great for testing.

VPN (Virtual Private Network) Secure tunnel for your internet connection.

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W

Window Manager (WM) Controls how windows look and behave. Lighter than full desktop environment.

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X

X11/Xorg Traditional display server. Being replaced by Wayland.

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Y

YAML Human-readable data format. Common in config files. Stands for: "YAML Ain't Markup Language"

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Z

Zsh Advanced shell with better features than Bash. Default in macOS now.

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Common commands quick reference

Command	What it does	Example
ls	List files	ls -la
cd	Change directory	cd /home
pwd	Show current directory	pwd
mkdir	Make directory	mkdir newfolder
rm	Remove file/directory	rm file.txt
cp	Copy files	cp source.txt dest.txt
mv	Move/rename files	mv old.txt new.txt
cat	Display file contents	cat file.txt
grep	Search in files	grep "text" file.txt
chmod	Change permissions	chmod 755 script.sh
chown	Change ownership	chown user:group file
df	Show disk usage	df -h
top/htop	Show running processes	htop
ps	List processes	ps aux
kill	Stop a process	kill 1234

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Pro tips

1. Tab Completion: Press Tab to auto-complete commands and file names
2. History: Use ↑ arrow to recall previous commands
3. Ctrl+C: Stop a running command
4. Ctrl+L: Clear the terminal screen
5. man [command]: Get help for any command

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Still confused?

That's normal. Linux has a learning curve. Check out:

• Common Issues - Troubleshooting help
• My Setup - See what hardware and software I actually use
• Contact - Ask me directly

Everyone starts somewhere.