Linux Bash Commands Cheat Sheet

Bash is the default shell on most Linux systems.

Basic Commands

Here are some basic bash commands:

Navigation

• cd <directory>: Change the current working directory to directory
• cd ..: Move up one directory level
• pwd: Print the current working directory

File and directory management

• ls: List the files and directories in the current directory
• ls <directory>: List the files and directories in directory
• ls -l: List the files and directories in the current directory in long format
• ls -a: List all files and directories, including hidden ones
• mkdir <directory>: Create a new directory directory
• touch <file>: Create a new file file
• cp <source> <destination>: Copy source to destination
• mv <source> <destination>: Move source to destination
• rm <file>: Delete file
• rmdir <directory>: Delete directory (if it is empty)

Text manipulation

• cat <file>: Print the contents of file to the terminal
• head <file>: Print the first 10 lines of file to the terminal
• tail <file>: Print the last 10 lines of file to the terminal
• sort <file>: Sort the lines of file
• grep <pattern> <file>: Print the lines in file that contain pattern

Process management

• ps: List the running processes
• top: Display the top running processes
• kill <pid>: Terminate the process with the process ID pid
• killall <process>: Terminate all processes with the name process

System information

• uname: Print the current system information
• uname -a: Print all system information
• uptime: Print the current uptime
• free: Print the memory usage
• df: Print the disk usage
• du: Print the directory space usage

Networking

• ping <host>: Send a ping request to host
• traceroute <host>: Print the route to host
• host <hostname>: Look up the IP address of hostname
• nslookup <hostname>: Look up the DNS information for hostname
• ifconfig: Print the network interface information

Users and groups

• whoami: Print the current user
• who: Print the users currently logged in
• adduser <user>: Add a new user user
• addgroup <group>: Add a new group group
• usermod -a -G <group> <user>: Add user to group
• passwd <user>: Change the password for user

Advanced Commands

Here are some advanced bash commands:

Shell scripts

• #! /bin/bash: Shebang indicating the path to the bash interpreter
• $0: The name of the script
• $1-$9: The first 9 arguments passed to the script
• $@: All arguments passed to the script
• $#: The number of arguments passed to the script
• $?: The exit status of the last command
• $!: The process ID of the last background command

Loops

• for i in <list>; do <commands>; done: Iterate through list, executing commands each time
• while <condition>; do <commands>; done: Execute commands while condition is true
• until <condition>; do <commands>; done: Execute commands until condition is true

  Conditionals

• if <condition>; then <commands>; fi: Execute commands if condition is true
• if <condition>; then <commands>; else <other commands>; fi: Execute commands if condition is true, otherwise execute other commands

Functions

• function <name> { <commands>; }: Define a function name with the commands commands
• <name> <arguments>: Call the function name with the arguments arguments

Variables

• <variable>=<value>: Set the value of variable to value
• $<variable>: Access the value of variable
• <variable>=$(<command>): Set the value of variable to the output of command

Redirection

• <command> > <file>: Redirect the output of command to file (overwrite)
• <command> >> <file>: Redirect the output of command to file (append)
• <command> < <file>: Redirect the input of command from file
• <command> 2> <file>: Redirect the error output of command to file
• <command> 2>> <file>: Redirect the error output of command to file (append)

Pipes

• <command1> | <command2>: Pipe the output of command1 as the input of command2

Background processes

• <command> &: Run command in the background

Aliases

• alias <name>='<command>': Set an alias name for the command command
• alias: List all aliases

Environment variables

• export <variable>=<value>: Set an environment variable variable to value
• echo $<variable>: Print the value of the environment variable variable

Shell options

• set -o <option>: Enable the shell option option
• set +o <option>: Disable the shell option option

History

• history: List the command history
• !<number>: Execute the command with the history number number
• !!: Execute the last command
• !<string>: Execute the most recent command starting with string