You cannot rely on the $! containing anything useful if a child process has set it and died. It sometimes happens, but there's nothing that garantees this. And it's very unportable.

And $? will contain whatever exit value the spawned program returned. This may be non-zero in the case of an error - but that is only a convention, not law. And programs can issue warnings on stderr, while completing a task succesfully.

Just use IPC::Open3.

-- Abigail