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Understanding the Linux File System and Basic Commands

Understanding the Linux File System and Basic Commands

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Yuv Raj Singh
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3 min read

Linux is a powerful and structured operating system with a unique file system hierarchy and a robust set of commands for file management. This post documents what I've learned about the Linux file system, methods to create files, and essential commands to manipulate them.

1. File System Hierarchy

Linux organizes files in a hierarchical structure, starting from the root directory (/). This differs from Windows, which uses drive letters (e.g., C:\).

Windows File System:

  • Root Directory: C:\

  • Common Subdirectories:

    • Program Files

    • Users

    • Program Files (x86)

    • PerfLogs

    • Logs

Linux File System:

  • Root Directory: /

  • Important Subdirectories:

    • /home – Home directory for users.

    • /root – Home directory for the root (admin) user.

    • /etc – Configuration files.

    • /usr – Default software installation directory.

    • /bin – Essential commands for all users.

    • /sbin – Commands used by root users.

    • /opt – Optional software packages.

    • /dev – Device files representing hardware (e.g., disks, USB devices).

2. Essential File Commands in Linux

The cat Command

The cat command is one of the most universal tools in Linux. Despite its simplicity, all it does is copy standard input to standard output, making it incredibly versatile.

What You Can Do with cat:

  1. Create a file

     cat > file1
 [Write data here]
 Ctrl+D  # Save and exit

  2. Concatenate multiple files

     cat file1 file2 > merged_file

  3. Copy content from one file to another

     cat file1 > file2

  4. Use tac (reverse cat) to display file content from bottom to top

     tac file1

The touch Command

The touch command is a simple yet powerful way to create files and manage timestamps.

What You Can Do with touch:

  1. Create an empty file

     touch file1

  2. Create multiple empty files

     touch file1 file2 file3

  3. Change all timestamps (access & modify time)

     touch -m file1

  4. Update access time without modifying content

     touch -a file1

What Are Timestamps?

  • Access Time (atime) – Last time the file was accessed.

  • Modify Time (mtime) – Last time the file content was modified.

  • Change Time (ctime) – Last time when file metadata was changed.

The vi and nano Editors

Both vi and nano are text editors in Linux, but they have some key differences.

vi Editor

  • Universally available – Comes pre-installed in all Linux distributions.

  • Modes: Command mode and Insert mode.

  • Common Commands:

      vi file1  # Open file in vi
  i  # Switch to insert mode
  Esc  # Exit insert mode
  :w  # Save file
  :q  # Quit editor
  :wq  # Save and quit
  :q!  # Quit without saving

nano Editor

  • Easier to use – More intuitive, but not always pre-installed.

  • Common Commands:

      nano file1  # Open file in nano
  Ctrl+O  # Save file
  Ctrl+X  # Exit editor
  Ctrl+K  # Cut text
  Ctrl+U  # Paste text

Wrapping Up

This exploration of Linux file management and commands has provided a solid foundation for understanding how files and directories work in a Linux environment. Each command serves a distinct purpose and can be combined in different ways to manage files efficiently.

🔹 Next Steps: I will be working on how to access and manage Linux using an EC2 instance on AWS.—-Stay tuned!

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