40 Most-Used Linux Commands You Should Know

Linux commands are powerful tools for interacting with and managing a Linux-based system. Here’s a list of 40 most-used Linux commands that are essential for beginners and advanced users alike.

File and Directory Management:

1. ls: List the contents of a directory.
   bash

   ls -l # Lists files with detailed information
2. cd: Change directory.
   bash

   cd /path/to/directory
3. pwd: Print the current working directory.
   bash

   pwd
4. mkdir: Create a new directory.
   bash

   mkdir new_directory
5. rmdir: Remove an empty directory.
   bash

   rmdir empty_directory
6. rm: Remove files or directories.
   bash

   rm file.txt # Remove a file rm -r folder # Remove a directory and its contents
7. cp: Copy files or directories.
   bash

   cp file1.txt /path/to/destination cp -r directory1 /path/to/destination
8. mv: Move or rename files or directories.
   bash

   mv file1.txt /path/to/destination mv oldname.txt newname.txt # Rename a file
9. touch: Create an empty file or update the timestamp of an existing file.
   bash

   touch newfile.txt
10. cat: Display the contents of a file.
    bash

    cat file.txt
11. more: View file content one screen at a time.
    bash

    Copy code

    more file.txt
12. less: View file content with more control (can scroll up and down).
    bash

    less file.txt
13. head: View the first few lines of a file.
    bash

    head file.txt
14. tail: View the last few lines of a file.
    bash

    tail file.txt tail -f file.txt # Follow file updates in real time (useful for logs)

System Information and Monitoring:

15. uname: Display system information.
    bash

    uname -a # Show detailed system info
16. df: Display disk space usage.
    bash

    df -h # Human-readable format
17. du: Show disk usage of files and directories.
    bash

    du -sh # Summary for a directory
18. top: Display real-time system processes and resource usage.
    bash

    top
19. htop: A more user-friendly alternative to top (needs to be installed).
    bash

    htop
20. free: Show memory usage.
    bash

    free -h # Human-readable format
21. ps: Display currently running processes.
    bash

    ps aux # Show detailed process list
22. kill: Terminate a process by its PID (Process ID).
    bash

    kill 1234 # Replace 1234 with the process PID
23. uptime: Show how long the system has been running.
    bash

    uptime
24. whoami: Display the current user.
    bash

    whoami
25. uname: Show system kernel information.
    bash

    uname -r # Show kernel version

File Permissions and Ownership:

26. chmod: Change file permissions.
    bash

    chmod 755 file.txt # Set read/write/execute permissions
27. chown: Change file or directory ownership.
    bash

    chown user:group file.txt
28. chgrp: Change group ownership of a file.
    bash

    chgrp groupname file.txt

Text Manipulation:

29. grep: Search for patterns within files.
    bash

    grep “search_term” file.txt grep -r “search_term” /path/to/directory # Search recursively
30. find: Search for files and directories.
    bash

    find /path/to/search -name “filename”
31. awk: Process and analyze text files.
    bash

    awk ‘{print $1}’ file.txt # Print the first column
32. sed: Stream editor for modifying files.
    bash

    sed ‘s/old/new/g’ file.txt # Replace all instances of ‘old’ with ‘new’

Networking:

33. ping: Test network connectivity.
    bash

    ping google.com
34. ifconfig: Display or configure network interfaces (older tool, replaced by ip).
    bash

    ifconfig
35. ip: Show/manipulate routing, devices, and tunnels (modern replacement for ifconfig).
    bash

    ip addr show
36. wget: Download files from the web.
    bash

    wget http://example.com/file.zip
37. curl: Transfer data from or to a server (supports more protocols than wget).
    bash

    curl http://example.com
38. netstat: Display network connections, routing tables, and interface statistics.
    bash

    netstat -tuln # Show listening ports
39. ssh: Connect to a remote server via Secure Shell.
    bash

    ssh user@remote_server
40. scp: Securely copy files between hosts over SSH.
    bash

    scp file.txt user@remote:/path/to/destination

Bonus:

• history: View command history.
  bash

  history
• alias: Create shortcuts for long commands.
  bash

  alias ll=’ls -l’

Mastering these commands can significantly improve your efficiency and control over a Linux system. Each command has multiple options and variations that extend their functionality even further!