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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 indeterminate 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.

  1. command is interactive and needs to read from the terminal for example
  2. 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. Also SIGCONT will not be sent to command, as it’s generally not needed with foreground processes, and can cause intermittent signal delivery issues with programs that are monitors themselves (like GDB for example).

-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 the command.

-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.

Exit status:

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

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