L-1.6: Imp Linux Commands(Operating System) | Must Watch for College/University & Competitive exams

Introduction

This tutorial provides a comprehensive guide to essential Linux commands, as discussed in the video "L-1.6: Imp Linux Commands(Operating System)". Understanding these commands is crucial for students in college and university, as well as for those preparing for competitive exams in computer science and IT.

Step 1: Navigating the File System

• Use pwd to print the current working directory.
• Use ls to list the contents of a directory.
  • Options:
    • ls -l for a detailed list.
    • ls -a to include hidden files.
• Change directories with cd [directory_name].
  • Use cd .. to go up one directory level.

Step 2: Managing Files and Directories

• Create a new directory with mkdir [directory_name].
• Remove a directory using rmdir [directory_name] (only if it's empty).
• To delete files, use rm [file_name].
  • Be cautious as this command does not move files to a trash bin.

Step 3: Viewing and Editing Files

• View file contents with cat [file_name].
• For paginated viewing, use more [file_name] or less [file_name].
• Edit files using nano [file_name] or vi [file_name] for more advanced editing.

Step 4: File Permissions and Ownership

• Check permissions with ls -l.
• Change file permissions using chmod [permissions] [file_name].
  • Example: chmod 755 [file_name] grants read, write, and execute permissions to the owner, and read and execute permissions to the group and others.
• Change file ownership with chown [user]:[group] [file_name].

Step 5: Process Management

• View running processes with ps or top for real-time updates.
• Kill a process using kill [process_id].
• Use killall [process_name] to terminate all instances of a process.

Step 6: Networking Commands

• Check network configuration with ifconfig or ip a.
• Use ping [hostname] to test connectivity to a network address.
• Retrieve the current directory of the user with pwd to ensure you are in the right directory when working with files.

Common Pitfalls to Avoid

• Always double-check the commands before executing, especially rm, as it permanently deletes files.
• Be cautious with file permissions to avoid unauthorized access or accidental modifications.
• Familiarize yourself with the man command (e.g., man ls) for manual pages that explain command usage.

Conclusion

Mastering these basic Linux commands will greatly enhance your efficiency in navigating and managing systems. Regular practice will help reinforce these skills, making you well-prepared for academic and competitive challenges. As a next step, consider exploring more advanced commands and scripting to further your Linux proficiency.