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EX200 Create simple shell scripts Practice Question

A complex script uses 'trap' to handle signals. The admin writes 'trap '' SIGINT' to ignore Ctrl+C, but later in the script they want to re-enable the default behavior. Which command restores the default behavior for SIGINT?

⚠ Common exam trap

The RHCSA exam often tests the subtle distinction between `trap '' signal` (ignore) and `trap - signal` (restore default), where candidates mistakenly think `trap signal` or `trap : signal` resets the handler.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

trap - SIGINT

`trap - SIGINT` resets the signal handler for SIGINT to its default behavior. The `trap '' SIGINT` command sets an empty action, which ignores the signal; using `trap - signal` removes that custom handler and restores the default action (typically terminating the process).

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • ✓

    trap - SIGINT

    Why this is correct

    trap - SIGINT resets SIGINT to its default disposition, undoing the earlier ignore. The hyphen tells the shell to restore default handling rather than run a command, which is exactly the re-enable behaviour the script needs after ignoring Ctrl+C.

  • ✗

    trap : SIGINT

    Why it's wrong here

    A colon is a valid shell builtin that does nothing, so this installs a no-op handler rather than clearing the trap. It is tempting because ':' is used as a placeholder command, but it leaves SIGINT ignored, whereas the correct syntax omits the action entirely to restore default.

  • ✗

    trap 2

    Why it's wrong here

    Passing the bare number 2 sets the handler to run the shell command named '2', not restore SIGINT's default disposition. It is tempting because signal numbers identify signals, but restoring default requires the signal name with no action argument, which resets the trap.

  • ✗

    trap SIGINT

    Why it's wrong here

    Supplying only the signal name with no action argument resets the trap, but 'trap SIGINT' is not valid syntax for that reset; the shell expects the action first, then the signal. It is tempting because it names the right signal, yet the argument order is reversed.

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Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This EX200 practice question is part of Courseiva's free Red Hat certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the EX200 exam.