acl_from_mode - Linux

Overview

acl_from_mode converts a numeric file permission mode to a textual Access Control List (ACL). It is primarily used to display the permissions for files and directories in a human-readable format.

Syntax

acl_from_mode [-a | -c | -f] [-d | -e | -l | -o] [file/directory]...

Options/Flags

  • -a, –acl: Show the ACL itself instead of the equivalent mode
  • -c, –canonical: Display the ACL in canonical format (without equivalent mode)
  • -d, –default: Display the default ACL
  • -e, –effective: Display the effective ACL (combining default and user-specified)
  • -f, –force: Displays ACLs regardless of the presence of the extended attributes
  • -l, –log: Output log messages
  • -o, –original: Display the original stored ACL instead of the effective ACL

Examples

To display the default ACL for a file:

acl_from_mode -d file.txt

To show the effective ACL for a directory:

acl_from_mode -e /some/directory

To convert a numeric mode to a textual ACL:

acl_from_mode 644

Common Issues

  • Permission denied: Ensure you have sufficient permissions to view or modify the ACLs.
  • Invalid file: Make sure the provided path is a valid file or directory.
  • Extended attributes not supported: On some filesystems, extended attributes (ACLs) may not be supported. Use the -f option to display ACLs regardless.

Integration

acl_from_mode can be integrated with other commands for advanced tasks:

  • Combine with ls: Display file permissions with ls -l and then pipe the output to acl_from_mode to view the ACLs.
  • Use in scripts: Embed acl_from_mode into scripts to automate ACL inspection and management.

Related Commands

  • chmod: Modify file permissions
  • getfacl: Display ACLs in a different format
  • setfacl: Modify ACLs