Linux Command Line Cheat Sheet

These are the commands that cover most day-to-day work in a Linux, macOS or WSL terminal. Replace the placeholders in <angle brackets> with your own values. Each command was run on a real system, except those that need a network, root rights or extra software.

Commands by task

Move around

Command	What it does
`pwd`	Print the current directory
`ls -la`	List all files with details, hidden ones included
`cd <dir>`	Change directory (`cd ..` up one level, `cd -` back, `cd` home)
`tree -L 2`	Show a folder as a tree, two levels deep (often needs installing)

Files and folders

Command	What it does
`mkdir -p a/b/c`	Create a folder and any missing parents
`cp -r src dest`	Copy a file or, with `-r`, a whole folder
`mv old new`	Move or rename
`rm -r folder`	Delete a folder and its contents; there is no recycle bin
`touch file`	Create an empty file or update its timestamp
`ln -s target link`	Create a symbolic link

Read files

Command	What it does
`cat file`	Print a whole file
`less file`	Page through a file (`q` quits, `/text` searches)
`head -n 20 file`	First 20 lines
`tail -n 20 file`	Last 20 lines (`tail -f` follows a growing log)
`wc -l file`	Count lines (`-w` words, `-c` bytes)

Search

Command	What it does
`grep -rn "text" .`	Search files under here for text, with line numbers
`grep -i "text" file`	Case-insensitive search (`-v` inverts, `-c` counts)
`find . -name "*.log"`	Find files by name
`find . -type f -mtime -1`	Files changed in the last day

Process text

Command	What it does
`sort file \| uniq -c`	Sort lines and count duplicates
`cut -d, -f1 file.csv`	Take the first comma-separated column
`sed 's/old/new/g' file`	Replace text on every line
`awk '{print $1}' file`	Print the first whitespace-separated field
`xargs`	Turn input lines into command arguments (`find ... \| xargs rm`)

Permissions and users

Command	What it does
`chmod 644 file`	Change permissions (see the chmod cheat sheet)
`chown user:group file`	Change owner and group
`sudo <command>`	Run one command as the administrator
`whoami`	Show your username

Processes

Command	What it does
`ps aux`	List all running processes
`top`	Live view of CPU and memory use (`q` quits)
`kill <pid>`	Ask a process to stop (`kill -9` forces it as a last resort)
`command &`	Run a command in the background (`jobs` lists, `fg` brings it back)

Disk and system

Command	What it does
`df -h`	Free space on each disk, human-readable
`du -sh folder`	Total size of a folder
`free -h`	Memory use
`uname -a`	Kernel and system information

Network

Command	What it does
`ping -c 4 host`	Check a host answers (four tries)
`curl -I https://example.com`	Fetch only the response headers
`ss -tuln`	List listening TCP and UDP ports
`ssh user@host`	Open a secure shell on another machine
`scp file user@host:/path`	Copy a file over SSH

Command	What it does
`tar -czf backup.tar.gz folder`	Create a gzip-compressed archive
`tar -xzf backup.tar.gz`	Extract it
`zip -r a.zip folder`	Create a ZIP file (often needs installing)

Pipes and redirection

command1 | command2 sends the output of the first command into the second.
command > file writes output to a file, replacing it; >> appends instead.
command 2> errors.txt redirects error messages; command > all.txt 2>&1 captures both.
command1 && command2 runs the second only if the first succeeded; || only if it failed.

Keyboard shortcuts in the shell

Keys	Effect
`Tab`	Complete a file or command name
`↑` / `↓`	Walk through command history
`Ctrl`+`R`	Search history
`Ctrl`+`C`	Stop the running command
`Ctrl`+`D`	End input or log out
`Ctrl`+`L`	Clear the screen
`Ctrl`+`A` / `Ctrl`+`E`	Jump to the start / end of the line

Be careful with

rm has no undo. rm -rf on the wrong path can erase a whole system; check the path with ls first, and never run rm -rf / or rm -rf ~.
sudo runs with full rights. Read a command before you put sudo in front of it.
chmod -R 777 makes everything writable by everyone; see chmod and File Permissions Cheat Sheet.
Pasting commands from the internet. Understand what a command does, especially anything that pipes curl into a shell.

For version control commands, see Git Cheat Sheet. For what each permission string means, see chmod and File Permissions Cheat Sheet.