Linux Command Cheat Sheet

This guide explains the most important and basic Linux commands in a simple way. Learning these will help you become more comfortable, confident, and efficient using Linux.

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📁 File and Directory Commands

• ls

  • Lists files and folders in the current folder.

• ls -l

  • Lists files with more details like size, date, and permissions.

• ls -a

  • Shows all files, including hidden ones (hidden files start with a dot .).

• cd /path/to/directory

  • Changes the current folder to another folder. Replace /path/to/directory with the folder you want to go to.

• pwd

  • Shows the full path of the current folder.

• mkdir folder_name

  • Creates a new folder. Replace folder_name with your desired name.

• rmdir folder_name

  • Deletes an empty folder.

• rm file_name

  • Deletes a file.

• rm -r folder_name

  • Deletes a folder and everything inside it.

• touch file_name

  • Creates a new empty file. If the file exists, it updates its time.

• cat file_name

  • Shows the content of the file.

• more file_name

  • Shows file content one page at a time.

• less file_name

  • Similar to more but with more features. You can scroll up and down.

• cp source_file target_file

  • Copies a file. Replace source_file with the file to copy and target_file with the new name.

• mv old_name new_name

  • Moves or renames a file or folder.

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🔐 SSH (Secure Shell)

• ssh user@host

  • Connects to another computer using your username and IP or hostname.

• ssh -p port user@host

  • Connects to another computer using a specific port.

• ssh-keygen -t rsa

  • Creates a secure key for logging into servers.

• ssh-copy-id user@host

  • Copies your key to another computer, so you don’t need to type the password each time.

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🔍 Searching

• grep pattern file

  • Searches for a word or phrase in a file.

• grep -r pattern folder

  • Searches for a word in all files inside a folder.

• find folder -name name*

  • Finds files that start with “name” in a folder.

• locate file_name

  • Quickly finds files by name (faster but might need updatedb).

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🔧 Process Management

• ps aux

  • Shows all running programs.

• ps aux | grep program_name

  • Finds a specific program by name.

• top

  • Shows live info about running programs (like Task Manager).

• kill PID

  • Stops a program by its ID (PID = Process ID).

• killall program_name

  • Stops all programs with the same name.

• bg

  • Lists background jobs or continues a stopped job in the background.

• fg

  • Brings a background job to the front so you can interact with it.

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🔒 File Permissions

• chmod +x file_name

  • Makes a file executable (can be run like a program).

• chmod 755 file_name

  • Gives read, write, and run permissions to owner, and read + run to others.

• chown user:group file_name

  • Changes who owns the file and its group.

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🌐 Networking

• ifconfig

  • Shows your network settings and IP addresses.

• ping host

  • Checks if a computer or website is reachable.

• traceroute host

  • Shows the path your data takes to reach another computer.

• netstat -tulnp

  • Lists open network ports and the programs using them.

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📦 Archiving and Compression

• tar cf archive.tar files

  • Creates a .tar archive from files.

• tar xf archive.tar

  • Extracts files from a .tar archive.

• gzip file_name

  • Compresses a file to save space (creates .gz).

• gunzip file.gz

  • Decompresses a .gz file.

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🖥️ System Info and Management

• uname -a

  • Shows details about your system and Linux version.

• df -h

  • Shows free space on your hard drive (in GB or MB).

• du -sh folder_name

  • Shows the size of a folder.

• free -m

  • Shows how much memory (RAM) is used or free.

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🔧 Misc Commands

• man command_name

  • Opens the manual/help page for a command.

• echo "text"

  • Prints text on the screen.

• date

  • Shows the current date and time.

• uptime

  • Tells how long your computer has been on.

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Use the man command to learn more about any of these commands. For example: man ls

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Bye for now,see you soon