linux-acl-guide

Linux ACL Management

This guide explains how to manage file and directory permissions using Access Control Lists (ACL) in Linux. It includes examples of basic file operations, ACL modifications, and recursive permission management.

Table of Contents

1.Commands Overview

2.Viewing ACL Permissions

3.Modifying ACL for user and group

• For a User
• For a Group

4.Modifying Other Permissions

5.Adding Multiple ACL Rules

6.Setting Mask Permissions

7.Recursive Permissions for a Directory

8.Removing ACL for a User

9.Resetting All ACL Permissions

10.Setting Default ACL for a Directory

1.Commands Overview

1. View ACL of a file

   getfacl <file>

2. Grant permissions

   setfacl -m u:<user>:<permissions> <file>

3. Remove permissions

   setfacl -x u:<user> <file>

4. Reset all ACLs

   setfacl -b <file>

5. Recursive ACL for directories

   setfacl -Rm u:<user>:<permissions> <directory>

6. Set default ACL for directories

   setfacl -m d:u:<user>:<permissions> <directory>

Examples

2.Viewing ACL Permissions

Displays the Access Control List (ACL) of the file f1.

3.Modifying ACL For User and Group

For a User:

Grants read-only (r) permission to user tom.

For Group:

Grants read, write, execute (rwx) permissions to group A1.

4.Modifying other Permissions

Grants write-only (w) permission to others.

5.Adding Multiple ACL Rules

Adds the following: User varun gets rw (read, write) permissions. Group B1 gets rx (read, execute) permissions. User jack gets rwx (read, write, execute) permissions.

6.Setting Mask Permissions

Sets the mask to read-only (r), which limits the effective permissions for group and other ACL entries.

7.Recursive Permissions for Directory

both have different permission but when we use -R recursive then

Recursively grants write permission to user tom for the directory abc and all its contents (like f2).

8.Removing ACL for a User

Removes the ACL entry for user varun.

9.Resetting All ACL Permissions

Removes all ACL entries from file f1.

10.Setting Default ACL for a Directory

Sets a default ACL for user don with rwx permissions. Any new file created inside abc will inherit these default permissions.

Notes

• Use ls -l to identify ACL-enabled files (+ sign).

• Use mask to limit the maximum effective permissions for ACL entries.

Author

This guide was created to assist with Linux ACL management and improve understanding of permission settings.