xref: /freebsd/bin/pwait/pwait.1 (revision 5bdce6ff546e00673f9f515d2165d02901e858aa)

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.Dd January 21, 2021
.Dt PWAIT 1
.Os
.Sh NAME
.Nm pwait
.Nd wait for processes to terminate
.Sh SYNOPSIS
.Nm
.Op Fl t Ar duration
.Op Fl ov
.Ar pid
\&...
.Sh DESCRIPTION
The
.Nm
utility will wait until each of the given processes has terminated.
.Pp
The following option is available:
.Bl -tag -width indent
.It Fl o
Exit when any of the given processes has terminated.
.It Fl t Ar duration
If any process is still running after
.Ar duration ,
.Nm
will exit.
The
.Ar duration
value can be integer or decimal numbers.
Values without unit symbols are interpreted as seconds.
.Pp
Supported unit symbols are:
.Bl -tag -width indent -compact
.It s
seconds
.It m
minutes
.It h
hours
.El
.It Fl v
Print the exit status when each process terminates or
.Ql timeout
if the timer goes off earlier.
.El
.Sh EXIT STATUS
The
.Nm
utility exits 0 on success, and >0 if an error occurs.
.Pp
If the
.Fl t
flag is specified and a timeout occurs, the exit status will be 124.
.Pp
Invalid pids elicit a warning message but are otherwise ignored.
.Sh EXAMPLES
Start two
.Xr sleep 1
processes in the background.
The first one will sleep for 30 seconds and the second one for one hour.
Wait for any of them to finish but no more than 5 seconds.
Since a timeout occurs the exit status is 124:
.Bd -literal -offset indent
$ sleep 30 & sleep 3600 &
[1] 1646
[2] 1647
$ pwait -o -t5 1646 1647
$?
124
.Ed
.Pp
Same as above but try to obtain the exit status of the processes.
In this case
.Ql timeout
is shown and the exit status is 124:
.Bd -literal -offset indent
$ sleep 30 & sleep 3600 &
[1] 1652
[2] 1653
$ pwait -v -t 5 1652 1653
timeout
$?
124
.Ed
.Pp
Start two
.Xr sleep 1
processes in the background sleeping for 30 and 40 seconds respectively.
Wait 60 seconds for any of them to finish and get their exit codes:
.Bd -literal -offset indent
$ sleep 30 & sleep 40 &
[1] 1674
[2] 1675
$ pwait -v -t 60 1674 1675
1674: exited with status 0.
1675: exited with status 0.
[1]-  Done                    sleep 30
[2]+  Done                    sleep 40
$ echo $?
0
.Ed
.Sh SEE ALSO
.Xr kill 1 ,
.Xr pkill 1 ,
.Xr ps 1 ,
.Xr wait 1 ,
.Xr kqueue 2
.Sh NOTES
.Nm
is not a substitute for the
.Xr wait 1
builtin
as it will not clean up any zombies or state in the parent process.
.Pp
To avoid deadlock,
.Nm
will ignore its own pid, if it is provided as a process id to wait for.
.Sh HISTORY
A
.Nm
command first appeared in SunOS 5.8.