Linux Command Line Cheat Sheet

cheatsheet linux bash command

Bash Commands

Command	Description
`uname -a`	Show system and kernel
`head -n1 /etc/issue`	Show distribution
`mount`	Show mounted filesystems
`date`	Show system date
`uptime`	Show uptime
`whoami`	Show your username
`man command`	Show manual for command

Bash Shortcuts

Shortcut	Description
`CTRL-c`	Stop current command
`CTRL-z`	Sleep program
`CTRL-a`	Go to start of line
`CTRL-e`	Go to end of line
`CTRL-u`	Cut from start of line
`CTRL-k`	Cut to end of line
`CTRL-r`	Search history
`!!`	Repeat last command
`!abc`	Run last command starting with abc
`!abc:p`	Print last command starting with abc
`!$`	Last argument of previous command
`ALT-.`	Last argument of previous command
`!*`	All arguments of previous command
`^abc^123`	Run previous command, replacing abc with 123

Bash Variables

Command	Description
`env`	Show environment variables
`echo $NAME`	Output value of the `$NAME` variable

Bash Variables (cont.)

Command	Description
`export NAME=value`	Set `$NAME` to value
`$PATH`	Executable search path
`$HOME`	Home directory
`$SHELL`	Current shell

IO Redirection

Command	Description
`cmd < file`	Input of cmd from file
`cmd1 <(cmd2)`	Output of cmd2 as file input to cmd1
`cmd > file`	Redirect stdout of cmd to file
`cmd > /dev/null`	Discard stdout of cmd
`cmd >> file`	Append stdout to file
`cmd 2> file`	Redirect stderr of cmd to file
`cmd 1>&2`	Send stdout to the same place as stderr
`cmd 2>&1`	Send stderr to the same place as stdout
`cmd &> file`	Redirect every output of cmd to file

Pipes

Command	Description
`cmd1 \| cmd2`	Pipe stdout of cmd1 to cmd2
`cmd1 \|& cmd2`	Pipe stderr of cmd1 to cmd2

Command Lists

Command	Description
`cmd1 ; cmd2`	Run cmd1 then cmd2
`cmd1 && cmd2`	Run cmd2 if cmd1 is successful
`cmd1
`cmd &`	Run cmd in a subshell

Directory Operations

Command	Description
`pwd`	Show current directory
`mkdir dir`	Create directory named dir
`cd dir`	Change directory to dir
`cd ..`	Go up one directory
`ls`	List files

ls Options

Option	Description
`-a`	Show all files (including hidden)
`-R`	Recursive listing
`-r`	Reverse order
`-t`	Sort by last modified
`-S`	Sort by file size
`-l`	Long listing format
`-1`	One file per line
`-m`	Comma-separated output
`-Q`	Quoted output

Search Files

Command	Description
`grep pattern files`	Search for pattern in files
`grep -i`	Case insensitive search
`grep -r`	Recursive search
`grep -v`	Inverted search
`grep -o`	Show only the matched part of file
`find /dir/ -name name*`	Find files starting with name in dir

Search Files (cont.)

Command	Description
`find /dir/ -user name`	Find files owned by name in dir
`find /dir/ -mmin num`	Find files modified less than num minutes ago in dir
`whereis command`	Find binary, source, or manual for command
`locate file`	Quick search for file using the system index

File Operations

Command	Description
`touch file1`	Create file file1
`cat file1 file2`	Concatenate files and output them
`less file1`	View and paginate file1
`file file1`	Determine the file type of file1
`cp file1 file2`	Copy file1 to file2
`mv file1 file2`	Move or rename file1 to file2
`rm file1`	Delete file1
`head file1`	Show the first 10 lines of file1
`tail file1`	Show the last 10 lines of file1
`tail -F file1`	Continuously display new lines from file1

Text Processing

Command	Description
`sort file`	Sort lines alphabetically
`sort -n file`	Sort numerically
`sort -r file`	Sort in reverse
`sort -u file`	Sort and remove duplicates
`uniq`	Filter adjacent duplicate lines
`uniq -c`	Count occurrences
`wc file`	Count lines, words, bytes
`wc -l file`	Count lines only
`cut -d: -f1 file`	Cut first field (delimiter `:`)
`tr 'a-z' 'A-Z'`	Translate lowercase to uppercase
`tr -d '\n'`	Delete newlines

sed (Stream Editor)

Command	Description
`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`	Edit file in place
`sed -n '5,10p' file`	Print lines 5-10
`sed '/pattern/d' file`	Delete lines matching pattern

awk

Command	Description
`awk '{print $1}' file`	Print first column
`awk -F: '{print $1}' file`	Print first column (delimiter `:`)
`awk '/pattern/ {print}' file`	Print lines matching pattern
`awk '{sum+=$1} END {print sum}'`	Sum first column
`awk 'NR==5' file`	Print line 5
`awk 'NF>0' file`	Print non-empty lines

Networking Commands

Command	Description
`ip addr`	Show IP addresses
`ip -4 addr`	Show IPv4 only
`ip route`	Show routing table
`ip link`	Show network interfaces
`ss -tuln`	Show listening ports (TCP/UDP)
`ss -tunap`	Show all connections with process
`ss -s`	Socket statistics summary

Network Diagnostics

Command	Description
`ping -c 4 host`	Send 4 ICMP packets
`traceroute host`	Trace route to host
`mtr host`	Continuous traceroute
`dig domain`	DNS lookup
`dig +short domain`	DNS lookup (short output)
`nslookup domain`	DNS lookup (alternative)
`host domain`	DNS lookup (simple)
`curl -I url`	Get HTTP headers only
`curl -o file url`	Download to file
`curl -X POST -d 'data' url`	POST request
`wget url`	Download file
`wget -r url`	Recursive download

Network Configuration

Command	Description
`nmcli device status`	NetworkManager device status
`nmcli connection show`	Show connections
`hostnamectl`	View/set hostname
`resolvectl status`	DNS resolver status

System Administration

systemd (Service Management)

Command	Description
`systemctl status service`	Check service status
`systemctl start service`	Start service
`systemctl stop service`	Stop service
`systemctl restart service`	Restart service
`systemctl enable service`	Enable at boot
`systemctl disable service`	Disable at boot
`systemctl list-units --type=service`	List all services
`systemctl list-units --failed`	List failed units
`journalctl -u service`	View service logs
`journalctl -f`	Follow system logs
`journalctl --since "1 hour ago"`	Logs from last hour

Disk Usage

Command	Description
`df -h`	Disk space (human readable)
`df -i`	Inode usage
`du -sh dir`	Directory size
`du -h --max-depth=1`	Size of immediate subdirs
`lsblk`	List block devices
`fdisk -l`	List disk partitions
`mount \| column -t`	Show mounts formatted

User Management

Command	Description
`id`	Current user info
`id username`	User info for username
`groups`	Show group membership
`useradd username`	Create user
`usermod -aG group user`	Add user to group
`passwd username`	Change password
`su - username`	Switch user
`sudo -i`	Root shell
`last`	Recent logins
`w`	Who is logged in

Watch a Command

Command	Description
`watch -n 5 'ntpq -p'`	Run the `ntpq -p` command every 5 seconds and display its output

Process Management

Command	Description
`ps`	Display a snapshot of current processes
`ps aux`	All processes with details
`ps aux \| grep name`	Find process by name
`top`	Show real-time processes
`htop`	Interactive process viewer
`kill pid`	Terminate process with ID pid
`kill -9 pid`	Force kill process
`pkill name`	Terminate process with name name
`killall name`	Terminate all processes starting with name
`pgrep name`	Get PID by name
`nohup cmd &`	Run command immune to hangups
`jobs`	List background jobs
`fg`	Bring job to foreground
`bg`	Resume job in background

Nano Shortcuts

Files

Shortcut	Description
`Ctrl-R`	Read file
`Ctrl-O`	Save file
`Ctrl-X`	Close file

Cut and Paste

Shortcut	Description
`ALT-A`	Start marking text
`CTRL-K`	Cut marked text or line
`CTRL-U`	Paste text

Navigate File

Shortcut	Description
`ALT-/`	Go to end of file
`CTRL-A`	Go to beginning of line
`CTRL-E`	Go to end of line
`CTRL-C`	Show line number
`CTRL-_`	Go to a specific line number

Search File

Shortcut	Description
`CTRL-W`	Find
`ALT-W`	Find next
`CTRL-\`	Search and replace

More info: nano-editor.org

Screen Shortcuts

Command	Description
`screen`	Start a screen session
`screen -r`	Resume a screen session
`screen -list`	List current screen sessions

Screen Shortcuts (cont.)

Shortcut	Description
`CTRL-A`	Activate screen commands
`CTRL-A c`	Create a new terminal instance
`CTRL-A n`	Switch to the next terminal instance
`CTRL-A p`	Switch to the previous terminal instance
`CTRL-A "`	Display a list of terminal instances
`CTRL-A A`	Rename the current terminal instance

More info: GNU Screen Manual

tmux Shortcuts

Command	Description
`tmux`	Start new session
`tmux new -s name`	New named session
`tmux ls`	List sessions
`tmux attach -t name`	Attach to session
`tmux kill-session -t name`	Kill session

Inside tmux (prefix: `CTRL-b`)

Shortcut	Description
`CTRL-b c`	New window
`CTRL-b n`	Next window
`CTRL-b p`	Previous window
`CTRL-b %`	Split vertical
`CTRL-b "`	Split horizontal
`CTRL-b arrow`	Switch pane
`CTRL-b d`	Detach
`CTRL-b [`	Scroll mode (q to exit)

File Permissions

Command	Description
`chmod 775 file`	Change mode of file to `775`
`chmod -R 600 folder`	Recursively change permissions of folder to `600`
`chown user:group file`	Change owner and group of file

File Permission Numbers

Calculate permission digits by summing the following values:

4 – read (r)
2 – write (w)
1 – execute (x)

Example: For permissions rwxr-xr--, calculate:

Owner: 4+2+1 = 7
Group: 4+0+1 = 5
Others: 4+0+0 = 4 Resulting in 754.

Common Permission Patterns

Permission	Meaning
`644`	Owner read/write, others read (files)
`755`	Owner full, others read/execute (scripts, dirs)
`600`	Owner read/write only (private files)
`700`	Owner full only (private dirs)
`777`	Everyone full access (avoid on production)

Archive and Compression

Command	Description
`tar -cvf archive.tar dir/`	Create tar archive
`tar -xvf archive.tar`	Extract tar archive
`tar -czvf archive.tar.gz dir/`	Create gzipped tar
`tar -xzvf archive.tar.gz`	Extract gzipped tar
`tar -tvf archive.tar`	List contents
`gzip file`	Compress file
`gunzip file.gz`	Decompress file
`zip -r archive.zip dir/`	Create zip
`unzip archive.zip`	Extract zip