Which pair of commands is used to manage access control lists on a file?

• A. chmod and chown
• B. setfacl and getfacl
• C. ls -l and stat
• D. mount and umount

Answer: (B)

Fine-grained access control in Linux uses ACLs to assign permissions to specific users and groups beyond the standard owner/owning group/other model. To manage these ACLs, use setfacl to set or modify ACL entries and getfacl to display them. For example, setfacl -m u:charlie:r-- file.txt grants user charlie read access without changing other permissions, and getfacl file.txt will show the current ACL entries (such as user:charlie:r--, user::rwx, group::r-x, other::r--, and any default ACLs on directories). In contrast, chmod adjusts only the basic rwx permissions, ls -l and stat show standard permissions and metadata but do not reveal or modify ACLs by default, and mount/umount relate to mounting filesystems rather than managing file permissions. So, for controlling ACL-based access, setfacl and getfacl are the correct tools.