waitpid
Wait for the termination of arbitrary processes.
TLDR
Sleep until all processes whose PIDs have been specified have exited
$ waitpid [pid1 pid2 ...]
Sleep for at most n seconds
$ waitpid --timeout [n] [pid1 pid2 ...]
Do not error if specified PIDs have already exited
$ waitpid --exited [pid1 pid2 ...]
Sleep until n of the specified processes have exited
$ waitpid --count [n] [pid1 pid2 ...]
Display help
$ waitpid -h
