Interview › Scripting (Bash, Groovy)
What is the trap command, and how do you use it for cleanup on exit? [Intermediate]
Answer
trap registers commands to run when the shell receives a signal or exits. I use trap for cleanup, such as deleting temporary files, releasing locks, or printing diagnostics on failure.
Technical explanation
trap 'cleanup' EXIT runs cleanup when the script exits for success or failure.
Signals like INT and TERM can be trapped to handle Ctrl+C or termination gracefully.
Keep trap handlers simple and robust because they may run during failure paths.
Hands-on example
tmpdir=$(mktemp -d)
cleanup() {
rm -rf "$tmpdir"
}
trap cleanup EXIT
trap 'echo "interrupted" >&2; exit 130' INT TERM
echo "working in $tmpdir
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