WAIT(1) BSD Reference Manual WAIT(1)
wait - await process completion
If invoked with no arguments, the wait utility waits until all existing
child processes in the background have terminated.
pid If a pid operand is specified, and it is the process ID of a
background child process that still exists, the wait utility
waits until that process has completed and consumes its status
information, without consuming the status information of any oth-
If a pid operand is specified that is not the process ID of a
child background process that still exists, wait exits without
waiting for any processes to complete.
The wait utility exits with one of the following values:
0 The wait utility was invoked with no operands and all of the ex-
isting background child processes have terminated, or the process
specified by the pid operand exited normally with 0 as its exit
>0 The specified process did not exist and its exit status informa-
tion was not available, or the specified process existed or its
exit status information was available, and it terminated with a
non-zero exit status.
If the specified process terminated abnormally due to the receipt of a
signal, the exit status information of wait contains that termination
status as well.
The wait command is expected to be IEEE Std1003.2 (``POSIX'') compatible.
4.4BSD June 5, 1993 1