23.6 timeout: Run a command with a time limit
timeout runs the given command and kills it if it is
still running after the specified time interval. Synopsis:
timeout [option] duration command [arg]...
command must not be a special built-in utility (see Special built-in utilities).
The program accepts the following options. Also see Common options.
Options must precede operands.
- Return the exit status of the managed command on timeout, rather than
a specific exit status indicating a timeout. This is useful if the
managed command supports running for an indeterminite amount of time.
- Don't create a separate background program group, so that
the managed command can use the foreground TTY normally.
This is needed to support timing out commands not started
directly from an interactive shell, in two situations.
- command is interactive and needs to read from the terminal for example
- the user wants to support sending signals directly to command
from the terminal (like Ctrl-C for example)
Note in this mode of operation, any children of command
will not be timed out.
- ‘-k duration’
- Ensure the monitored command is killed by also sending a ‘KILL’
signal, after the specified duration. Without this option, if the
selected signal proves not to be fatal, timeout does not kill
- ‘-s signal’
- Send this signal to command on timeout, rather than the
default ‘TERM’ signal. signal may be a name like ‘HUP’
or a number. See Signal specifications.
duration is a floating point number followed by an optional unit:
‘s’ for seconds (the default)
‘m’ for minutes
‘h’ for hours
‘d’ for days
A duration of 0 disables the associated timeout.
Note that the actual timeout duration is dependent on system conditions,
which should be especially considered when specifying sub-second timeouts.
124 if command times out
125 if timeout itself fails
126 if command is found but cannot be invoked
127 if command cannot be found
137 if command is sent the KILL(9) signal (128+9)
the exit status of command otherwise