Which command removes all ACL entries from a file named file1?

• A. setfacl --clear file1
• B. setfacl -x all file1
• C. setfacl --remove-all file1
• D. setfacl --remove-default file1

Answer: (C)

The concept being tested is how to remove every additional access rule attached to a file, i.e., clearing all ACL entries so the file is governed only by its standard permission bits (owner, group, others).

The best command is the one that instructs the tool to remove all ACL entries in one go. This option tells setfacl to delete every ACL entry associated with the file, leaving no extra per-file permissions behind. After this, only the normal file permissions remain in effect.

Why the other forms aren’t suitable: removing a single entry with -x requires specifying exactly which ACL entry to delete, so it cannot wipe out everything in one go. Removing only the default ACL would affect only default entries (often used for directories), not the entire ACL set on the file. The explicit remove-all option targets the complete clearing of all ACL entries, which is precisely what you want when you need to reset the file to standard permissions.