SC2173 – ShellCheck Wiki

SIGKILL/SIGSTOP can not be trapped.

Problematic code:

trap 'echo "unkillable"' KILL

Correct code:

Not applicable. This is not possible.

Rationale:

SIGKILL and SIGSTOP can not be caught/ignored (according to POSIX and as implemented on platforms including Linux and FreeBSD). Trying to trap this signal has undefined results.

Exceptions:

None. If you come across one, please file an issue about it.

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