50 Linux Commands every developer NEED to know with example

Here are 50 Linux commands that every developer should know, along with a brief description and an example of each command:

1. ls - Lists the contents of a directory.

   • Example: ls will list the contents of the current directory. ls /usr/local will list the contents of the /usr/local directory.

2. pwd - Prints the current working directory.

   • Example: pwd will print the full path of the current working directory.

3. cd - Changes the current working directory.

   • Example: cd /usr/local will change the current working directory to /usr/local.

4. mkdir - Creates a new directory.

   • Example: mkdir mydir will create a new directory called mydir.

5. mv - Moves a file or directory.

   • Example: mv file.txt /usr/local/ will move the file file.txt to the /usr/local directory.

6. cp - Copies a file or directory.

   • Example: cp file.txt /usr/local/ will copy the file file.txt to the /usr/local directory.

7. rm - Removes a file or directory.

   • Example: rm file.txt will remove the file file.txt, while rm -r mydir will remove the directory mydir and all of its contents.

8. touch - Creates a new empty file.

   • Example: touch file.txt will create a new empty file called file.txt.

9. ln - Creates a link to a file or directory.

   • Example: ln -s /usr/local/file.txt file.txt will create a symbolic link to /usr/local/file.txt called file.txt in the current directory.

10. cat - Displays the contents of a file.

    • Example: cat file.txt will display the contents of the file file.txt in the terminal.

11. clear - Clears the terminal screen.

    • Example: clear will clear the contents of the terminal screen.

12. echo - Prints a message to the terminal.

    • Example: echo "Hello, world!" will print the message "Hello, world!" to the terminal.

13. less - Views a file with pagination.

    • Example: less file.txt will allow you to view the contents of file.txt one page at a time.

14. man - Displays the manual page for a command.

    • Example: man ls will display the manual page for the ls command, which describes its usage and options.

15. uname - Displays information about the current system.

    • Example: uname -a will display all information about the current system, including the kernel version and machine hardware name.

16. whoami - Displays the current user.

    • Example: whoami will display the username of the current user.

17. tar - Archives and compresses files and directories.

    • Example: tar -czf archive.tar.gz directory/ will create a compressed archive called archive.tar.gz from the contents of the directory directory.

18. grep - Searches for a pattern in a file.

    • Example: grep "error" log.txt will search the file log.txt for the pattern "error" and print any lines that match.

19. head - Displays the first few lines of a file.

    • Example: head -n 10 file.txt will display the first 10 lines of file.txt.

20. tail - Displays the last few lines of a file.

    • Example: tail -n 10 file.txt will display the last 10 lines of file.txt.

21. diff - Compares the differences between two files.

    • Example: diff file1.txt file2.txt will compare the contents of file1.txt and file2.txt and print the differences between them.

22. cmp - Compares the contents of two files byte by byte.

    • Example: cmp file1.txt file2.txt will compare the contents of file1.txt and file2.txt byte by byte and report any differences.

23. comm - Compares the contents of two sorted files line by line.

    • Example: comm file1.txt file2.txt will compare the contents of file1.txt and file2.txt, which should both be sorted, and print the lines that are unique to each file.

24. sort - Sorts the lines of a file.

    • Example: sort file.txt will sort the lines of file.txt alphabetically.

25. export - Exports a shell variable.

    • Example: export VARNAME="value" will create a shell variable called VARNAME with the value "value".

26. zip - Compresses files into a ZIP archive.

    • Example: zip archive.zip file1.txt file2.txt will create a ZIP archive called archive.zip containing the files file1.txt and file2.txt.

27. unzip - Extracts files from a ZIP archive.

    • Example: unzip archive.zip will extract the contents of the archive.zip ZIP archive.

28. ssh - Connects to a remote server using the SSH protocol.

    • Example: ssh [e-mail] will connect to the server at example.com as the user user.

29. service - Controls system services.

    • Example: service apache2 start will start the Apache web server.

30. ps - Displays information about running processes.

    • Example: ps aux will display a list of all running processes and their resource usage.

31. kill - Sends a signal to a process to terminate it.

    • Example: kill 12345 will send the signal to terminate the process with the process ID 12345.

32. killall - Terminates all processes with a specified name.

    • Example: killall firefox will terminate all processes with the name firefox.

33. df - Displays information about available disk space on mounted filesystems.

    • Example: df -h will display the available disk space in a human-readable format (e.g., in gigabytes or megabytes).

34. mount - Mounts a filesystem.

    • Example: mount /dev/sda1 /mnt/mydisk will mount the partition /dev/sda1 at the mount point /mnt/mydisk.

35. chmod - Changes the permissions of a file or directory.

    • Example: chmod 755 file.txt will give read, write, and execute permissions to the owner and read and execute permissions to everyone else for the file file.txt.

36. chown - Changes the ownership of a file or directory.

    • Example: chown user:group file.txt will change the owner of file.txt to user and the group ownership to group.

37. ifconfig - Configures network interface parameters.

    • Example: ifconfig eth0 up will enable the network interface eth0.

38. traceroute - Traces the path of packets to a destination.

    • Example: traceroute example.com will trace the path of packets from the current system to the destination example.com.

39. wget - Downloads a file from the internet.

    • Example: wget https://example.com/file.zip will download the file file.zip from https://example.com.

40. ufw - A frontend for managing a firewall.

    • Example: ufw allow ssh will allow incoming connections to the SSH service.

41. iptables - A firewall management tool for Linux.

    • Example: iptables -A INPUT -p tcp --dport 80 -j ACCEPT will allow incoming connections to TCP port 80 (the default port for HTTP).

42. apt - A package manager for Debian-based systems.

    • Example: apt update will update the list of available packages.

43. sudo - Allows a user to run a command with the privileges of the superuser (root).

    • Example: sudo apt update will update the list of available packages with root privileges.

44. cal - Displays a calendar.

    • Example: cal will display the current month's calendar.

45. alias - Creates an alias for a command.

    • Example: alias ll='ls -alF' will create an alias ll that runs the command ls -alF.

46. dd - Copies data from one location to another.

    • Example: dd if=/dev/sda of=disk.img will create an image file called disk.img of the contents of the device /dev/sda.

47. whereis - Shows the locations of a command.

    • Example: whereis ls will show the locations of the ls command on the system.

48. whatis - Shows a short description of a command.

    • Example: whatis ls will show a short description of the ls command.

49. top - Displays information about running processes.

    • Example: top will display a list of running processes and their resource usage in real-time.

50. passwd - Changes the password for a user.

    • Example: passwd user1 will prompt you to enter and confirm a new password for the user user1.

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