📖 Guide

Linux Commands Cheat Sheet — Complete Reference

Every essential Linux command, from file management to networking to shell scripting. Searchable and organized.

204 commands across 12 categories

File & Directory File Viewing & Editing File Permissions Text Processing Archives & Compression Process Management Networking Disk & Storage User Management System Information Shell Scripting Basics Package Management

File & Directory

Command	Description
`ls`	List directory contents
`ls -la`	List all files with details (including hidden)
`ls -lh`	List with human-readable file sizes
`ls -lt`	List sorted by modification time (newest first)
`cd <dir>` e.g. cd /var/log	Change directory
`cd ~`	Go to home directory
`cd -`	Go to previous directory
`pwd`	Print current working directory
`mkdir <dir>`	Create a directory
`mkdir -p <path>` e.g. mkdir -p src/components/ui	Create nested directories
`rm <file>`	Remove a file
`rm -r <dir>`	Remove directory recursively
`rm -rf <dir>`	Force remove without confirmation ⚠️
`cp <src> <dest>`	Copy file
`cp -r <src> <dest>`	Copy directory recursively
`mv <src> <dest>`	Move or rename file/directory
`touch <file>`	Create empty file or update timestamp
`ln -s <target> <link>`	Create symbolic link
`find <dir> -name '.js'` e.g. find . -name '.log'	Find files by name pattern
`find <dir> -type f -mtime -7`	Find files modified in last 7 days
`find . -size +100M`	Find files larger than 100MB
`locate <pattern>`	Fast file search using index database
`tree`	Show directory tree structure
`tree -L 2`	Show tree with depth limit
`stat <file>`	Show detailed file information

File Viewing & Editing

Command	Description
`cat <file>`	Display file contents
`cat -n <file>`	Display with line numbers
`less <file>`	View file with pagination (scrollable)
`head <file>`	Show first 10 lines
`head -n 20 <file>`	Show first 20 lines
`tail <file>`	Show last 10 lines
`tail -n 50 <file>`	Show last 50 lines
`tail -f <file>`	Follow file in real-time (great for logs)
`wc <file>`	Count lines, words, and bytes
`wc -l <file>`	Count lines only
`diff <file1> <file2>`	Compare two files line by line
`diff -u <file1> <file2>`	Unified diff format
`nano <file>`	Open file in nano editor
`tee <file>` e.g. echo 'hi' \| tee output.txt	Read stdin, write to stdout AND file

File Permissions

Command	Description
`chmod 755 <file>`	Set permissions (owner: rwx, group/other: rx)
`chmod +x <file>`	Make file executable
`chmod -R 644 <dir>`	Set permissions recursively
`chmod u+w,g-w <file>`	Add owner write, remove group write
`chown <user>:<group> <file>`	Change file owner and group
`chown -R <user> <dir>`	Change owner recursively
`chgrp <group> <file>`	Change group ownership
`umask 022`	Set default permission mask for new files

Text Processing

Command	Description
`grep <pattern> <file>` e.g. grep 'error' app.log	Search for pattern in file
`grep -r <pattern> <dir>`	Recursive search in directory
`grep -i <pattern> <file>`	Case-insensitive search
`grep -n <pattern> <file>`	Show line numbers with matches
`grep -c <pattern> <file>`	Count matching lines
`grep -v <pattern> <file>`	Invert match (show non-matching lines)
`grep -E 'pat1\|pat2' <file>`	Extended regex (OR pattern)
`grep -l <pattern> *.js`	List filenames with matches
`sed 's/old/new/' <file>`	Replace first occurrence per line
`sed 's/old/new/g' <file>`	Replace all occurrences
`sed -i 's/old/new/g' <file>`	In-place replacement (modify file)
`sed -n '5,10p' <file>`	Print lines 5 through 10
`sed '/pattern/d' <file>`	Delete lines matching pattern
`awk '{print $1}' <file>` e.g. ls -l \| awk '{print $5, $9}'	Print first column
`awk -F: '{print $1}' /etc/passwd`	Use custom field separator
`awk '{sum+=$1} END {print sum}'`	Sum values in first column
`sort <file>`	Sort lines alphabetically
`sort -n <file>`	Sort numerically
`sort -r <file>`	Sort in reverse order
`sort -u <file>`	Sort and remove duplicates
`uniq`	Remove adjacent duplicate lines
`uniq -c`	Count occurrences of each line
`cut -d: -f1 <file>`	Cut field 1 using : delimiter
`cut -c1-10 <file>`	Cut characters 1-10 from each line
`tr 'a-z' 'A-Z'` e.g. echo 'hello' \| tr 'a-z' 'A-Z'	Translate lowercase to uppercase
`tr -d '\n'`	Delete newline characters
`xargs <cmd>` e.g. find . -name '*.tmp' \| xargs rm	Build commands from stdin
`xargs -I {} <cmd> {}` e.g. cat urls.txt \| xargs -I {} curl {}	Use placeholder for each input

Archives & Compression

Command	Description
`tar -czf archive.tar.gz <dir>`	Create gzipped tar archive
`tar -xzf archive.tar.gz`	Extract gzipped tar archive
`tar -xzf archive.tar.gz -C <dir>`	Extract to specific directory
`tar -tf archive.tar.gz`	List archive contents
`tar -cjf archive.tar.bz2 <dir>`	Create bzip2 compressed archive
`gzip <file>`	Compress file (replaces original)
`gunzip <file>.gz`	Decompress gzip file
`zip -r archive.zip <dir>`	Create zip archive
`unzip archive.zip`	Extract zip archive
`unzip -l archive.zip`	List zip contents

Process Management

Command	Description
`ps aux`	List all running processes
`ps aux \| grep <name>`	Find process by name
`top`	Interactive process viewer
`htop`	Enhanced interactive process viewer
`kill <pid>`	Terminate process by PID (SIGTERM)
`kill -9 <pid>`	Force kill process (SIGKILL)
`killall <name>`	Kill all processes by name
`pkill -f <pattern>`	Kill processes matching pattern
`bg`	Resume suspended job in background
`fg`	Bring background job to foreground
`jobs`	List background/suspended jobs
`<cmd> &` e.g. sleep 100 &	Run command in background
`nohup <cmd> &`	Run command immune to hangups
`nice -n 10 <cmd>`	Run with lower priority
`renice -n 5 -p <pid>`	Change priority of running process
`pgrep <name>`	Find process ID by name
`lsof -i :8080`	Show process using port 8080

Networking

Command	Description
`curl <url>` e.g. curl https://api.example.com	Make HTTP request
`curl -o file <url>`	Download file
`curl -X POST -d '{...}' <url>`	POST request with data
`curl -H 'Authorization: Bearer token' <url>`	Request with custom header
`curl -s <url> \| jq .`	Fetch JSON and pretty-print
`wget <url>`	Download file
`wget -r <url>`	Recursive download (mirror site)
`ssh user@host`	Connect to remote machine
`ssh -i key.pem user@host`	SSH with private key
`ssh -L 8080:localhost:80 user@host`	Local port forwarding
`scp <file> user@host:<path>`	Copy file to remote machine
`scp user@host:<file> <local>`	Copy file from remote machine
`rsync -avz <src> <dest>`	Sync files (fast, incremental)
`rsync -avz --delete <src> <dest>`	Sync and delete extra files at dest
`ping <host>`	Test connectivity
`ping -c 4 <host>`	Ping 4 times then stop
`ss -tuln`	Show listening TCP/UDP ports
`ss -tp`	Show TCP connections with process info
`dig <domain>` e.g. dig google.com	DNS lookup
`dig +short <domain>`	DNS lookup (IP only)
`nslookup <domain>`	Query DNS servers
`ip addr`	Show network interfaces and IPs
`ip route`	Show routing table
`traceroute <host>`	Trace packet route to host
`netcat -l -p 8080`	Listen on port 8080

Disk & Storage

Command	Description
`df -h`	Show disk space usage (human-readable)
`du -sh <dir>`	Show directory size
`du -sh * \| sort -rh \| head`	Top 10 largest items in current dir
`du -ah <dir> \| sort -rh \| head -20`	Top 20 largest files in directory tree
`lsblk`	List block devices (disks, partitions)
`mount`	Show mounted filesystems
`mount <device> <dir>`	Mount a filesystem
`umount <dir>`	Unmount a filesystem
`fdisk -l`	List disk partitions
`ncdu <dir>`	Interactive disk usage analyzer

User Management

Command	Description
`whoami`	Show current username
`id`	Show user ID, group ID, and groups
`who`	Show logged-in users
`w`	Show logged-in users and their activity
`useradd <user>`	Create a new user
`useradd -m -s /bin/bash <user>`	Create user with home dir and bash shell
`usermod -aG <group> <user>` e.g. usermod -aG docker daniel	Add user to group
`userdel -r <user>`	Delete user and home directory
`passwd <user>`	Change user password
`groups <user>`	Show user's groups
`su - <user>`	Switch to another user
`sudo <cmd>`	Run command as root
`sudo -u <user> <cmd>`	Run command as another user
`visudo`	Safely edit sudoers file

System Information

Command	Description
`uname -a`	Show all system information
`hostname`	Show or set system hostname
`uptime`	Show system uptime and load average
`free -h`	Show memory usage (human-readable)
`lscpu`	Show CPU information
`lsb_release -a`	Show Linux distribution info
`cat /etc/os-release`	Show OS version details
`dmesg \| tail`	Show recent kernel messages
`date`	Show current date and time
`timedatectl`	Show/set time zone and NTP status
`env`	Show all environment variables
`printenv <VAR>`	Show specific environment variable
`which <cmd>`	Show full path of a command
`type <cmd>`	Show how a command would be interpreted

Shell Scripting Basics

Command	Description
`#!/bin/bash`	Shebang — first line of a bash script
`VAR="value"`	Set a variable (no spaces around =)
`$VAR or ${VAR}`	Reference a variable
`$(command)` e.g. DATE=$(date +%Y-%m-%d)	Command substitution
`export VAR=value`	Set environment variable for child processes
`if [ condition ]; then ... fi`	If statement
`[ -f file ]`	Test if file exists
`[ -d dir ]`	Test if directory exists
`[ -z "$VAR" ]`	Test if variable is empty
`[ "$a" = "$b" ]`	String equality test
`[ $a -eq $b ]`	Numeric equality test
`for i in 1 2 3; do ... done`	For loop
`for f in *.txt; do ... done`	Loop over files
`while [ condition ]; do ... done`	While loop
`case $VAR in pat1) ... ;; esac`	Case/switch statement
`function name() { ... }`	Define a function
`$1, $2, $@, $#`	Script arguments: first, second, all, count
`$?`	Exit code of last command (0 = success)
`set -e`	Exit script on any error
`set -x`	Print each command before executing (debug)
`cmd1 && cmd2`	Run cmd2 only if cmd1 succeeds
`cmd1 \|\| cmd2`	Run cmd2 only if cmd1 fails
`cmd1 \| cmd2`	Pipe stdout of cmd1 to stdin of cmd2
`cmd > file`	Redirect stdout to file (overwrite)
`cmd >> file`	Redirect stdout to file (append)
`cmd 2>&1`	Redirect stderr to stdout
`cmd &> file`	Redirect both stdout and stderr to file

Package Management

Command	Description
`apt update`	Update package index (Debian/Ubuntu)
`apt upgrade`	Upgrade all packages
`apt install <pkg>` e.g. apt install nginx	Install a package
`apt remove <pkg>`	Remove a package
`apt search <query>`	Search for packages
`apt list --installed`	List installed packages
`dnf install <pkg>`	Install package (Fedora/RHEL)
`dnf update`	Update all packages (Fedora/RHEL)
`pacman -S <pkg>`	Install package (Arch)
`pacman -Syu`	Full system upgrade (Arch)
`snap install <pkg>`	Install snap package
`snap list`	List installed snaps