Choosing an octal mode with SUID | LinuC Level 1 101 Exam original practice question

1.02.1Basic

Set tool to ordinary mode 755 and add set-user-ID.

Which four-digit mode 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.

Detailed explanation

Correct4755

Correct. 4 for SUID followed by 755 gives 4755.

Incorrect2755

Incorrect. 2 selects SGID.

Incorrect1755

Incorrect. 1 selects the sticky bit.

Incorrect0755

Incorrect. 0 sets no special bit.

An example you can run in a temporary verification environment.

tmp=$(mktemp); chmod 4755 "$tmp"; stat -c '%a' "$tmp"; rm -f "$tmp"

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-101-387

EnvironmentGNU coreutils 9.x / 空の一時ファイル

Last technical review2026-08-13