linux-cheat-sheet

This Cheat Sheet coontains most commnly and very uncommonly used linux commands.

Table of Contents:

1. File and Directory Management
2. File Content Manipulation
3. File Permissions
4. System Monitoring
5. Network Commands
6. Process Management
7. Archiving and Compression
8. User Management
9. Package Management (Debian/Ubuntu)
10. Others

1. File and Directory Management

• ls: Lists files and directories.

  • Example: ls -l (detailed list view)

• cd: Changes the current directory.

  • Example: cd /home/user

• pwd: Displays the current working directory.

  • Example: pwd

• mkdir: Creates a new directory.

  • Example: mkdir new_folder

• rmdir: Removes empty directories.

  • Example: rmdir old_folder

• rm: Deletes files or directories.

  • Example: rm file.txt, rm -r folder (recursive delete)

• cp: Copies files or directories.

  • Example: cp file1.txt file2.txt

• mv: Moves or renames files or directories.

  • Example: mv file1.txt new_file.txt

• touch: Creates a new empty file.

  • Example: touch newfile.txt

• find: Searches for files and directories.

  • Example: find / -name file.txt

• locate: Finds files and directories quickly using a database.

  • Example: locate file.txt

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2. File Content Manipulation

• cat: Displays the content of a file.

  • Example: cat file.txt

• tac: Displays the content of a file in reverse.

  • Example: tac file.txt

• less: Opens a file for viewing (scrollable).

  • Example: less file.txt

• more: Views file content (less advanced than less).

  • Example: more file.txt

• head: Displays the first few lines of a file.

  • Example: head -n 10 file.txt

• tail: Displays the last few lines of a file.

  • Example: tail -n 10 file.txt

• nano: Opens a file in a simple text editor.

  • Example: nano file.txt

• vim: Opens a file in the Vim text editor.

  • Example: vim file.txt

• wc: Counts words, lines, and characters in a file.

  • Example: wc file.txt

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3. File Permissions

• chmod: Changes file or directory permissions.

  • Example: chmod 755 file.txt

• chown: Changes file ownership.

  • Example: chown user:group file.txt

• chgrp: Changes group ownership of a file.

  • Example: chgrp group file.txt

• umask: Sets default permissions for new files and directories.

  • Example: umask 022

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4. System Monitoring

• top: Displays real-time processes and resource usage.

• htop: An interactive version of top (needs to be installed).

• ps: Lists running processes.

  • Example: ps aux

• df: Shows disk space usage.

  • Example: df -h

• du: Displays disk usage of a directory or file.

  • Example: du -h folder

• free: Displays memory usage.

  • Example: free -h

• uptime: Shows system uptime.

  • Example: uptime

• who: Displays logged-in users.

  • Example: who

• w: Shows who is logged in and what they are doing.

  • Example: w

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5. Network Commands

• ping: Tests network connectivity to a host.

  • Example: ping google.com

• ifconfig: Displays or configures network interfaces.

  • Example: ifconfig eth0

• ip: Configures network interfaces and routing (modern replacement for ifconfig).

  • Example: ip addr

• netstat: Displays network connections and statistics.

  • Example: netstat -tuln

• ss: Displays detailed network statistics (faster than netstat).

  • Example: ss -tuln

• wget: Downloads files from the internet.

  • Example: wget http://example.com/file.txt

• curl: Transfers data from a URL.

  • Example: curl http://example.com

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6. Process Management

• kill: Terminates a process using its PID.

  • Example: kill 1234

• killall: Terminates all processes with a specific name.

  • Example: killall firefox

• jobs: Lists background jobs.

  • Example: jobs

• fg: Brings a background job to the foreground.

  • Example: fg %1

• bg: Resumes a background job.

  • Example: bg %1

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7. Archiving and Compression

• tar: Archives files into a tarball.

  • Example: tar -cvf archive.tar files/

• gzip: Compresses files using the gzip algorithm.

  • Example: gzip file.txt

• gunzip: Decompresses gzip files.

  • Example: gunzip file.txt.gz

• zip: Compresses files into a zip archive.

  • Example: zip archive.zip file.txt

• unzip: Extracts files from a zip archive.

  • Example: unzip archive.zip

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8. User Management

• whoami: Displays the current logged-in user.

  • Example: whoami

• id: Displays user ID, group ID, and other information.

  • Example: id

• adduser: Adds a new user.

  • Example: sudo adduser username

• passwd: Changes the password for a user.

  • Example: passwd

• usermod: Modifies a user account.

  • Example: usermod -aG groupname username

• deluser: Deletes a user account.

  • Example: sudo deluser username

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9. Package Management (Debian/Ubuntu)

• apt-get: Installs, upgrades, or removes packages.

  • Example: sudo apt-get install package-name

• apt: A user-friendly alternative to apt-get.

  • Example: sudo apt install package-name

• dpkg: Installs or removes .deb packages.

  • Example: sudo dpkg -i package.deb

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10. Others

• echo: Displays text.

  • Example: echo "Hello, World!"

• date: Shows or sets the system date and time.

  • Example: date

• cal: Displays a calendar.

  • Example: cal

• shutdown: Shuts down the system.

  • Example: sudo shutdown now

• reboot: Reboots the system.

  • Example: sudo reboot

• alias: Creates a shortcut for a command.

  • Example: alias ll='ls -l'

• clear: Clears the terminal screen.

  • Example: clear

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This repo is created by Kausalya N P

Users can copy this for educational purpose.