Permission notation (rwxrwxrwx) in Linux CLI - Commands & Configuration

Introduction

Files and folders in Linux have permissions that control who can read, write, or run them. These permissions are shown as a string like rwxrwxrwx, which tells you what actions are allowed for the owner, group, and others.

When you want to check who can open or change a file on your computer.

When you need to make a script executable so it can run.

When you want to restrict access to a private folder so only you can see it.

When you share files on a server and want to control who can edit or delete them.

When troubleshooting why a program cannot access a file due to permission issues.

Commands

This command lists the file details including its permission notation, so you can see who can read, write, or execute the file.

Terminal

ls -l example.txt

Expected Output

-rw-r--r-- 1 user user 1234 Apr 27 12:00 example.txt

→

-l - Shows detailed information including permissions, owner, size, and date.

This command adds execute permission for the file owner (user), allowing them to run the file if it is a script or program.

Terminal

chmod u+x example.txt

Expected Output

No output (command runs silently)

→

u+x - Adds execute permission to the user (owner) only.

Check the permissions again to confirm that the execute permission was added for the owner.

Terminal

ls -l example.txt

Expected Output

-rwxr--r-- 1 user user 1234 Apr 27 12:00 example.txt

→

-l - Shows detailed file information including updated permissions.

Key Concept

If you remember nothing else from this pattern, remember: the rwxrwxrwx string shows read, write, and execute permissions for owner, group, and others in that order.

Common Mistakes

Trying to run a script without execute permission.

The system will deny running the file because execute permission is missing.

Use chmod u+x filename to add execute permission for the owner.

Changing permissions without checking current settings.

You might accidentally remove needed permissions or give too many permissions.

Always check permissions first with ls -l before changing them.

Summary

Use ls -l to see the permission notation of files and folders.

The rwxrwxrwx string shows permissions for owner, group, and others in sets of three.

Use chmod with flags like u+x to add execute permission for the owner.