If an EXIT trap is executed after receipt of a terminating signal, waiting on a process substitution within the trap can fail:
$ (trap 'wait $!; echo $?' EXIT; : <(:); kill 0) -bash: wait: pid 83694 is not a child of this shell 127 Interestingly, if an external command or a subshell is executed after the process substitution is started but prior to receipt of the signal, the `wait' works fine: $ (trap 'wait $!; echo $?' EXIT; : <(:); (:); kill 0) 0
