acl_calc_mask - Linux

Overview

acl_calc_mask is a command-line tool used to calculate the Access Control List (ACL) mask for a given set of permissions. It finds applications in scenarios involving ACL management and privilege assignment, particularly within the Linux environment.

Syntax

acl_calc_mask [-u] [-g] [-o] [-m <mask>] [<acl_spec> ...] <filename>

Options/Flags

| Option/Flag | Description |
|—|—|
| -u | Calculate user-based ACL mask |
| -g | Calculate group-based ACL mask |
| -o | Calculate other/default ACL mask |
| -m <mask> | Calculate mask based on specified octal mask |

Examples

Example 1: Calculate user-based ACL mask for permissions on a file

acl_calc_mask -u rw-r--r-- example.txt

Output:

0644

Example 2: Calculate group-based ACL mask for the same file

acl_calc_mask -g - rw-r--r-- example.txt

Output:

0055

Common Issues

  • Insufficient permissions: Ensure the user running the command has sufficient permissions to read the ACL and modify files if necessary.
  • Invalid ACL specification: Verify the syntax of the ACL specification entered.
  • Non-existent file: Check if the specified filename exists before attempting to calculate the ACL mask.

Integration

acl_calc_mask can be integrated with other commands for more complex operations:

  • Find files with specific ACL permissions: Use find to locate files with matching ACL permissions and calculate the ACL mask for each.
  • Set ACL permissions: Calculate the desired ACL mask using acl_calc_mask and then set permissions using setfacl.

Related Commands

  • getfacl
  • restorecon
  • setfacl