LFCS Certification Filesystem Permissions and ACLs 5

Question 1

Which command removes only the named user ACL entry for 'dave' from 'data.csv'?

Accepted Answer

setfacl -x u:dave data.csv

Answer

setfacl -x removes a specific ACL entry without affecting other entries; -b would remove all ACL entries.

Question 2

A process runs as UID 1001. A file has owner UID 1001 and permissions '---rwxrwx'. Can the owner read the file?

Accepted Answer

No — the kernel checks only the owner bits, which are '---'

Answer

Linux permission checks stop at the first matching category; if the process UID matches the file owner, only the owner permission bits are evaluated, regardless of group or other bits.

Question 3

What does 'umask 0022' mean when a user creates a new directory?

Accepted Answer

The directory gets permissions 755 (777 minus 022)

Answer

Directories start with a base of 777; subtracting umask 022 yields 755 (rwxr-xr-x).

Question 4

Which special permission bit, when set on an executable, causes it to run with the group privileges of the file's group rather than the invoking user's group?

Accepted Answer

Setgid (chmod g+s)

Answer

The setgid bit on an executable makes it run with the file's group ID as the effective GID of the process.

Question 5

How can an administrator apply ACLs recursively to all files under '/srv/project'?

Accepted Answer

setfacl -R -m u:alice:rwx /srv/project

Answer

The -R flag in setfacl applies the specified ACL modification recursively to all files and directories under the target path.

LFCS Certification Practice Test

LFCS Certification Practice Test

LFCS Certification Filesystem Permissions and ACLs 5