setfacl

Setfacl

The setfacl command is used to set Access Control Lists (ACLs) on files and directories. An ACL is a way to assign permissions to users or groups, beyond just the owner, group, and other three categories.

While chmod can only change the ownership of a file or directory, setfacl allows you to add additional access rules that specify which user or group has read, write, or execute permissions. This is particularly useful when working with shared files or directories where multiple users need to have different levels of access.

Use cases:

• Granting specific users or groups permission to modify a file or directory without changing the ownership.
• Creating public folders that are accessible by anyone, while still maintaining some level of security.
• Setting up hierarchical permissions within a directory structure, making it easier to manage complex ACLs.

Hacks and tips:

• To remove all ACLs from a file or directory, use setfacl -x.
• To set the default ACL for a directory, use setfacl -d followed by the desired ACL settings.
• Use getfacl to view the current ACL settings on a file or directory before making changes with setfacl.

Experience level: Advanced

This command is suitable for users who have a solid grasp of Linux permissions and are familiar with using commands like chmod, chown, and groups. While it’s not essential for beginners to learn setfacl first, having some experience with file system management and Linux security concepts will make understanding the use cases and options more accessible.

Additional resources:

For those looking to dive deeper into ACLs and their uses in Linux, consider exploring the following:

• The official getfacl and setfacl manual pages (man getfacl, man setfacl)
• Online tutorials or blog posts that cover ACL basics and more advanced scenarios
• Books on Linux security and system administration that discuss ACLs and other permission management techniques