timeout(1) - CHERI manual pages with mandoc

NAME

timeout — run a command with a time limit

SYNOPSIS

Timeout starts the command with its arg list. If the command is still running after duration, it is killed by sending the signal, or SIGTERM if the -s option is unspecified. The special duration, zero, signifies no limit. Therefore, a signal is never sent if duration is 0.

The signal dispositions inherited by the command are the same as the dispositions that timeout inherited, except for the signal that will be sent upon timeout, which is reset to take the default action and should terminate the process.

If timeout receives the SIGALRM signal, it will behave as if the time limit has been reached and send the specified signal to command. For any other signals delivered to timeout, it will propagate them to command, with the exception of SIGKILL and SIGSTOP. If you want to prevent the command from being timed out, send SIGKILL to timeout.

The options are as follows:

-f, --foreground: Only time out the command itself, but do not propagate signals to its descendants. See the IMPLEMENTATION NOTES section for more details.
-k time, --kill-after time: Send a SIGKILL signal if command is still running after time since the first signal was sent.
-p, --preserve-status: Always exit with the same status as command, even if the timeout was reached.
-s signal, --signal signal: Specify the signal to send on timeout. By default, SIGTERM is sent.
-v, --verbose: Show information to stderr(4) about timeouts, signals to be sent, and the command exits.

Duration Format

The duration and time are non-negative integer or real (decimal) numbers, with an optional suffix specifying the unit. Values without an explicit unit are interpreted as seconds.

Supported unit suffixes are:

s: seconds
m: minutes
h: hours
d: days

IMPLEMENTATION NOTES

If the --foreground option is not specified, timeout runs as the reaper (see also procctl(2)) of the command and its descendants, and will wait for all the descendants to terminate. This behavior might cause surprises if there are descendants running in the background, because they will ignore SIGINT and SIGQUIT signals. For example, the following command that sends a SIGTERM signal will complete in 2 seconds:

$ timeout -s TERM 2 sh -c 'sleep 4
  & sleep 5'

However, this command that sends a SIGINT signal will complete in 4 seconds:

$ timeout -s INT 2 sh -c 'sleep 4
  & sleep 5'

EXIT STATUS

If the time limit was reached and the --preserve-status option is not specified, the exit status is 124. Otherwise, timeout exits with the same exit status as the command. For example, timeout will terminate itself with the same signal if the command is terminated by a signal.

If an error occurred, the following exit values are returned:

125: An error other than the two described below occurred. For example, an invalid duration or signal was specified.
126: The command was found but could not be executed.
127: The command could not be found.

EXAMPLES

Run sleep(1) with a time limit of 4 seconds. Since the command completes in 2 seconds, the exit status is 0:

$ timeout 4 sleep 2
$ echo $?
0

Run sleep(1) for 4 seconds and terminate process after 2 seconds. The exit status is 124 since --preserve-status is not used:

$ timeout 2 sleep 4
$ echo $?
124

Same as above but preserving status. The exit status is 128 + signal number (15 for SIGTERM) for most shells:

$ timeout --preserve-status 2 sleep 4
$ echo $?
143

Same as above but sending SIGALRM (signal number 14) instead of SIGTERM:

$ timeout --preserve-status -s SIGALRM 2 sleep 4
$ echo $?
142

Try to fetch(1) the PDF version of the FreeBSD Handbook. Send a SIGTERM signal after 1 minute and send a SIGKILL signal 5 seconds later if the process refuses to stop:

$ timeout -k 5s 1m fetch \
> https://download.freebsd.org/ftp/doc/en/books/handbook/book.pdf

NAME

SYNOPSIS

DESCRIPTION

Duration Format

IMPLEMENTATION NOTES

EXIT STATUS

EXAMPLES

SEE ALSO

STANDARDS

HISTORY

AUTHORS