Linux Beginner

What is Chmod?

A command to change file and directory access permissions using numeric or symbolic notation.

Chmod modifies read (r=4), write (w=2), and execute (x=1) permissions for owner, group, and others. Numeric: chmod 755 file (owner=rwx, group=rx, others=rx). Symbolic: chmod u+x file (add execute for owner).

Common permissions: 644 (files — owner rw, others read), 755 (directories/scripts — owner rwx, others rx), 600 (private files — owner only). The -R flag applies recursively. Understanding permissions is fundamental to Linux security.

Related Terms

Redundant Array of Independent Disks — a technology combining multiple physical drives into a single unit for performance, redundancy, or both.

A versatile command-line tool for transferring data using various network protocols, commonly used for API testing.

Security-Enhanced Linux — a mandatory access control system that confines programs to minimum required privileges beyond standard file permissions.

The primary command for managing systemd services, including starting, stopping, enabling, and checking service status.

The systemd journal daemon that collects and stores log data from services, the kernel, and boot messages in a structured binary format.

A command that displays kernel ring buffer messages, useful for diagnosing hardware and driver issues.

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