NAME
timeout —
signal command after delays
SYNOPSIS
timeout |
[-fpv] [-s
signal] [-k
kill-after] signal-after
program
[argument]… |
DESCRIPTION
Executes program arguments, but sends it
signal (default SIGTERM) after
signal-after, and SIGKILL
after an additional delay of kill-after, if
specified.
If -f was not specified,
timeout becomes the process group leader and sends
signals to the process group: this has the added benefit of signaling all of
the program's children.
Additionally, it will also forward all instances of
SIGTERM, SIGINT,
SIGHUP, SIGQUIT, and the
specified signal it receives to the child (or process
group). Be wary about attempting to forward
SIGALRM.
All times are in non-monotonic wall-clock time. All sent
signals are followed by a SIGCONT. Delays of
0 disable the
corresponding timer.
OPTIONS
-f,--foreground- Do not become a process group leader and signal the child directly.
-p,--preserve-status- Return the child's shell-style exit status instead of 124 when the child dies after timing out.
-v,--verbose- Note all signals being sent to the standard error stream.
-s,--signal=signal- Send signal instead of
SIGTERMafter signal-after expires. -k,--kill-after=duration- Send
SIGKILLduration after signal-after.
Time Intervals
signal-after and kill-after are floating-point amounts of seconds, optionally suffixed with one of the following cumulative multipliers:
This is the same format as sleep(1).Signal Name
If signal starts with a digit, it's presumed to be a numerical signal value. Otherwise, if it starts with "SIG", that prefix is stripped for the purposes of further matching. All string comparisons are case-insensitive.
On platforms with sys_signame(3) (the BSD), signal is matched directly to the array.
Elsewhere, it's matched to the signal names known at
compile time; the null signal is known as "Signal 0". Real-time
signals, if any, can be specified in the format
"RTinteger",
where integer is a decimal number
(NetBSD-style), or
"RTMIN+integer"
and
"RTMAX-integer"
(procps-style). Real-time signals must fall in
[SIGRTMIN, SIGRTMAX] to be
accepted.
ENVIRONMENT
PATH- In which program is searched, confer execvp(3).
SIGNALS
SIGTERM,SIGINT,SIGHUP,SIGQUIT, signal- Caught and forwarded to the child (or process group).
SIGALRM- Used for timing signal-after and
kill-after. May be specified as
signal, but sending it to
timeoutwill only advance it to sending the next signal. SIGTTIN,SIGTTOU- Ignored: this means that "
timeout1cat&" will not stop, while "cat&" would, confer termios(4).
EXIT STATUS
- 124
- program exited after signal
was sent and
-pwasn't specified. - 128+signal
(128+
SIGKILL) - program exited due to a signal. This matches shells' synthesised exit statuses for signal terminations.
- 125
- An error occurred.
- 126
- program exists, but couldn't be executed for a different reason.
- 127
- program wasn't found.
- All others
- returned by program either before
signal-after or with
-p.
EXAMPLES
Limit a command to a second of run-time:
$timeout1sleep20$echo$?124
Emulate pipe shutter after a half-minute:
$timeout-vfsPIPE0.5myes|wctimeout: yes (14539): sending SIGPIPE 568057856 568057856 1136115712
-f, as otherwise
timeout also kills wc.
Resort to killing:
$timeout-k1s-sHUP1nohupsleep20 nohup: input shut, output and error in nohup.out timeout: nohup (group): sending Hangup timeout: nohup (group): sending Killed Killed$echo$?137
-p, the exit status
appears to be
137 —
this is because SIGKILL is unblockable, and, when sent
to the process group, arrived to timeout itself, since
under an interactove shell, each pipeline is a process group.
SEE ALSO
credentials(7) for the implications of
timeout becoming a process group leader.
kill -l and
signal(7) for a list of available signals.
HISTORY
Originates from the GNU system in coreutils 7.0; also present in
NetBSD 7.0 and FreeBSD 11.0,
although those versions miss -v and
un-SIG-prefixed
-s.
The
hd delay suffixes and
short versions of -fp are extensions.