The Linux command line (often referred to as shell, terminal, console, prompt) is a text interface to your computer running one of the Linux operating systems.

Navigating the command line might seem like a maze at first glance, but it's really the key to unleashing the true power of your Linux system. This cheat sheet we've put together isn't just a list of commands; think of it as your handy guide through the wilderness of system management and troubleshooting, a companion for both beginners itching to explore and experts needing a quick reference.

We are compiling a fairly comprehensive list that covers various categories, including file management, system monitoring, network commands, and others, to serve as a foundational reference for you. This cheat sheet aims to provide a balanced mixture of commands - from the most commonly used to those that are crucial for specific troubleshooting and system management tasks.

File Management

• ls: Lists files and directories within the current directory.
• cd <directory>: Changes the current directory to the specified one.
• pwd: Displays the current directory path.
• cp <source> <destination>: Copies files or directories.
• mv <source> <destination>: Moves files or directories, also used for renaming.
• rm <file>: Deletes a file. Use -r for directories.
• mkdir <directory>: Creates a new directory.
• rmdir <directory>: Deletes an empty directory.
• find: Searches for files and directories.
• touch <file>: Creates a new file or updates the timestamp of an existing file.

System Monitoring and Management

• top: Displays an interactive list of running processes.
• ps: Shows a snapshot of current processes.
• free: Shows memory usage.
• df: Displays disk space usage for file systems.
• du: Shows the disk usage of files and directories.
• htop: An interactive process viewer (more detailed than top).

Network Commands

• ping <host>: Checks connectivity to a host.
• ifconfig: Displays or configures network interfaces. (ip a in newer systems)
• netstat: Displays network connections, routing tables, and interface statistics.
• ss: Another utility to investigate sockets.
• wget <URL>: Downloads files from the internet.
• curl <URL>: Transfers data from or to a server.

File Permissions

• chmod <permissions> <file>: Changes the file's mode.
• chown <user>:<group> <file>: Changes the file owner and group.
• umask: Sets the default permission for new files and directories.

Text Processing

• grep <pattern> <files>: Searches for a pattern in files.
• sed: Stream editor for filtering and transforming text.
• awk: An entire programming language designed for text processing.

Archive and Compression

• tar: Creates and extracts tar archives.
• gzip <file>: Compresses or decompresses files.
• zip, unzip: Compress and decompress zip files.

Package Management (Debian/Ubuntu)

• apt-get update: Updates the package list.
• apt-get upgrade: Upgrades all upgradable packages.
• apt-get install <package>: Installs a new package.
• apt-get remove <package>: Removes a package.

Package Management (RHEL/CentOS/Fedora)

• yum check-update: Checks for available package updates.
• yum update: Updates all upgradable packages.
• yum install <package>: Installs a new package.
• yum remove <package>: Removes a package.

General

• echo text: Displays a line of text.
• which <command>: Shows the full path of (shell) commands.
• man <command>: Displays the manual page for the command.

This cheat sheet covers essential commands but is by no means exhaustive. Each command comes with a plethora of options and nuances, best explored through their manual pages (man command).

And remember, the true power of Linux lies in combining these commands using pipes (|) and redirections (>, <) to perform complex tasks efficiently.