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.\" Copyright (c) 2014 Baptiste Daroussin <bapt@FreeBSD.org>
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.Dd June 26, 2023
.Dt TIMEOUT 1
.Os
.Sh NAME
.Nm timeout
.Nd run a command with a time limit
.Sh SYNOPSIS
.Nm
.Op Fl -signal Ar sig | Fl s Ar sig
.Op Fl -preserve-status
.Op Fl -kill-after Ar time | Fl k Ar time
.Op Fl -foreground
.Ar duration
.Ar command
.Op Ar args ...
.Sh DESCRIPTION
.Nm
starts the
.Ar command
with its
.Ar args .
If the
.Ar command
is still running after
.Ar duration ,
it is killed.
By default,
.Dv SIGTERM
is sent.
The special
.Ar duration ,
zero, signifies no limit.
Therefore a signal is never sent if
.Ar duration
is 0.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl -preserve-status
Exit with the same status as
.Ar command ,
even if it times out and is killed.
.It Fl -foreground
Do not propagate timeout to the children of
.Ar command .
.It Fl s Ar sig , Fl -signal Ar sig
Specify the signal to send on timeout.
By default,
.Dv SIGTERM
is sent.
.It Fl k Ar time , Fl -kill-after Ar time
Send a
.Dv SIGKILL
signal if
.Ar command
is still running after
.Ar time
after the first signal was sent.
.El
.Sh DURATION FORMAT
.Ar duration
and
.Ar time
are non-negative integer or real (decimal) numbers, with an optional
unit-specifying suffix.
Values without an explicit unit are interpreted as seconds.
.Pp
Supported unit symbols are:
.Bl -tag -width indent -compact
.It Cm s
seconds
.It Cm m
minutes
.It Cm h
hours
.It Cm d
days
.El
.Sh EXIT STATUS
If the timeout was not reached, the exit status of
.Ar command
is returned.
.Pp
If the timeout was reached and
.Fl -preserve-status
is set, the exit status of
.Ar command
is returned.
If
.Fl -preserve-status
is not set, an exit status of 124 is returned.
.Pp
If
.Ar command
exits after receiving a signal, the exit status returned is the signal number
plus 128.
.Pp
If
.Ar command
refers to a non-existing program, the exit status returned is 127.
.Pp
If
.Ar command
is an otherwise invalid program, the exit status returned is 126.
.Pp
If an invalid parameter is passed to
.Fl s
or
.Fl k ,
the exit status returned is 125.
.Sh EXAMPLES
Run
.Xr sleep 1
with a time limit of 4 seconds.
Since the command completes in 2 seconds, the exit status is 0:
.Bd -literal -offset indent
$ timeout 4 sleep 2
$ echo $?
0
.Ed
.Pp
Run
.Xr sleep 1
for 4 seconds and terminate process after 2 seconds.
124 is returned since no
.Fl -preserve-status
is used:
.Bd -literal -offset indent
$ timeout 2 sleep 4
$ echo $?
124
.Ed
.Pp
Same as above but preserving status.
Exit status is 128 + signal number (15 for
.Va SIGTERM ) :
.Bd -literal -offset indent
$ timeout --preserve-status 2 sleep 4
$ echo $?
143
.Ed
.Pp
Same as above but sending
.Va SIGALRM
(signal number 14) instead of
.Va SIGTERM :
.Bd -literal -offset indent
$ timeout --preserve-status -s SIGALRM 2 sleep 4
$ echo $?
142
.Ed
.Pp
Try to
.Xr fetch 1
the PDF version of the
.Fx
Handbook.
Send a
.Va SIGTERM
signal after 1 minute and send a
.Va SIGKILL
signal 5 seconds later if the process refuses to stop:
.Bd -literal -offset indent
$ timeout -k 5s 1m fetch \\
> https://download.freebsd.org/ftp/doc/en/books/handbook/book.pdf
.Ed
.Sh SEE ALSO
.Xr kill 1 ,
.Xr nohup 1 ,
.Xr signal 3 ,
.Xr daemon 8
.Sh HISTORY
The
.Nm
command first appeared in
.Fx 10.3 .
.Sh AUTHORS
.An Baptiste Daroussin Aq Mt bapt@FreeBSD.org
and
.An Vsevolod Stakhov Aq Mt vsevolod@FreeBSD.org