Permissions & Security (Chmod/Chown/ACLs/SELinux/AppArmor)

Stop chasing ACL permission ghosts with getfacl and setfacl

🧩 The Challenge

You finally fixed the permissions on a shared directory but some random user still gets a permission denied error. It turns out standard Linux permissions are too blunt, and you missed a hidden ACL entry that’s been overriding everything.

💡 The Fix

Use Access Control Lists to give specific users or groups access without wrecking your owner and group settings. It saves you from having to create fake groups just to let one person write to a folder.

getfacl -R /path/to/directory
setfacl -m u:username:rw /path/to/directory
setfacl -x u:username /path/to/directory

⚙️ Why It Works

These tools talk directly to the filesystem’s extended attributes to layer granular permissions on top of the traditional mode bits. Once you start using them, you’ll see a plus sign at the end of your ls -l output, which is your immediate clue that something else is going on.

🚀 Pro-Tip: Always run getfacl -R first so you don’t overwrite existing rules you’ve forgotten about.

Linux Tips & Tricks | © ngelinux.com | 9/2/2026