Linux is the operating system of choice for many DevOps professionals due to its stability, security, and open-source nature.

Mastering Linux commands is crucial for effective DevOps practices as it empowers engineers to streamline tasks, automate processes, and manage infrastructure efficiently.

In this article, we'll explore a list of essential Linux commands that are indispensable for DevOps practitioners.

1. ls - List Files and Directories: The ls command is fundamental for navigating the file system. It displays the contents of a directory, allowing users to view files and directories. Common flags include -l for detailed information and -a to show hidden files.

    ls -l
   

2. cd - Change Directory: The cd command is used to change the current working directory. Navigating through the file system is a routine task in DevOps, and mastering cd is essential.

    cd /path/to/directory
   

3. pwd - Print Working Directory: To know the current directory path, use the pwd command. It helps in understanding the current context while working on the command line.

    pwd
   

4. cp - Copy Files and Directories: The cp command allows the copying of files and directories. This is vital for creating backups, duplicating files, or deploying configuration files.

    cp source_file destination
   

5. mv - Move or Rename Files: The mv command is versatile, enabling users to both move and rename files or directories. This is valuable for organizing and managing the file system efficiently.

    mv old_name new_name
   

6. rm - Remove Files or Directories: Deleting unnecessary files or directories is a common task. The rm command, used with caution, helps in removing files and directories.

    rm file_name
   

7. mkdir - Create Directories: Creating directories is essential for organizing code, logs, or any other project-related files. The mkdir command serves this purpose.

    mkdir directory_name
   

8. touch - Create Empty Files: The touch command is useful for creating empty files, often needed when initializing configuration files or placeholders.

    touch file_name
   

9. grep - Search Text in Files: The grep command is powerful for searching text within files. DevOps engineers often use it for log analysis, configuration file parsing, and more.

    grep "search_term" file_name
   

10. vi or nano - Text Editors: A solid understanding of a terminal-based text editor like vi or nano is crucial for quick edits to configuration files or scripts.

    vi file_name
    

11. chmod - Change File Permissions: Managing file permissions is crucial for securing sensitive data. The chmod command allows users to modify permissions for files and directories.

    chmod 755 file_name
    

12. chown - Change File Ownership: In a multi-user environment, changing file ownership might be necessary. The chown command facilitates this process.

    chown user:group file_name
    

13. ps - Process Status: Monitoring processes is essential in DevOps. The ps command provides information about active processes on the system.

    ps aux
    

14. top or htop - System Monitoring: For a real-time overview of system performance, commands like top or htop are invaluable. They display information about CPU, memory, and processes.

    top
    

15. df - Disk Free: Checking disk space is critical for preventing system outages. The df command provides information about disk space usage.

    df -h
    

16. du - Disk Usage: To determine the disk space used by specific directories, the du command comes in handy.

    du -sh /path/to/directory
    

17. wget/curl - Download Files from the Internet:

    DevOps often involves fetching files or scripts from the web. Both wget and curl are commands that facilitate downloading resources.

    bashCopy codewget http://example.com/file.zip
    

    bashCopy codecurl -O http://example.com/file.zip
    

18. ssh - Secure Shell:

    The ssh command is vital for secure remote access to servers. It enables encrypted communication and remote command execution.

    bashCopy codessh username@remote_server
    

19. iptables - Firewall Configuration:

    cssCopy codeFor controlling and configuring the Linux kernel firewall, the `iptables` command is essential. It allows you to set rules for packet filtering, network address translation, and more.
    
    ```bash
    sudo iptables -A INPUT -p tcp --dport 22 -j ACCEPT
    ```
    

Common sudo Commands in DevOps:

In the Linux world, the sudo command is a powerful tool that allows users to execute commands with elevated privileges. The term "sudo" stands for "superuser do," and it enables a permitted user to execute a command as the superuser (root) or another user, according to the security policy configured in the sudoers file.

1. File and Directory Operations:

   • Copy a file with elevated permissions:

       sudo cp source_file destination
     

   • Remove a file or directory with elevated permissions:

       sudo rm -r file_or_directory
     

2. Package Management:

   • Install or update packages:

       sudo apt-get install package_name
     

   • Update the package database:

       sudo apt-get update
     

3. System Configuration:

   • Edit system configuration files with a text editor:

       sudo nano /etc/config_file.conf
     

   • Restart a service:

       sudo systemctl restart service_name
     

4. User Management:

   • Add a new user:

       sudo adduser new_username
     

   • Change a user's password:

       sudo passwd username
     

5. System Monitoring:

   • View real-time system information:

       sudo top
     

   • Check disk space usage:

       sudo df -h
     

Mastering these essential Linux commands is a foundational step for any DevOps engineer. From managing files and directories to monitoring system performance, these commands empower professionals to efficiently navigate and control Linux-based systems.

Continuous learning and practical application of these commands contribute to a robust skill set for effective DevOps practices.