Adding SGID to a directory | LinuC Level 1 101 Exam original practice question

1.02.1Basic

Preserve shared's ordinary permissions and add SGID for group inheritance.

Which command is appropriate?

Hint 1: Focus on the requirement

Identify what must change and what must remain unchanged. Then choose the command whose scope matches that requirement.

Hint 2: Check each command's role

Separate commands that display information, change state, remove data, or affect a child process.

chmod u+s shared: Incorrect. u+s sets SUID.
chmod g+x shared: Incorrect. g+x adds ordinary group execute/search permission only.
chmod o+t shared: Incorrect. o+t sets sticky bit.
chmod g+s shared: Correct. chmod g+s shared adds the directory SGID bit.

Detailed explanation

Incorrectchmod u+s shared

Incorrect. u+s sets SUID.

Incorrectchmod g+x shared

Incorrect. g+x adds ordinary group execute/search permission only.

Incorrectchmod o+t shared

Incorrect. o+t sets sticky bit.

Correctchmod g+s shared

Correct. chmod g+s shared adds the directory SGID bit.

An example you can run in a temporary verification environment.

tmp=$(mktemp -d); chmod 775 "$tmp"; chmod g+s "$tmp"; stat -c '%A %a' "$tmp"; chmod 700 "$tmp"; rmdir "$tmp"

drwxrwsr-x 2775

Foundation review

Check whether the command acts on the current shell, a new process, an existing process, or a file.

Use the supplied command and compare the output with the expected result.

Question IDKL-101-388

EnvironmentGNU coreutils 9.x / 一時ディレクトリ

Last technical review2026-08-13