shtimeout

#!/usr/bin/env bash

# Based on http://www.bashcookbook.com/bashinfo/source/bash-4.0/examples/scripts/timeout3

scriptName="${0##*/}"

function printUsage() {
    cat <<EOF

Synopsis
    $scriptName timeout command

    Execute a command with a time-out.

    Upon time-out expiration SIGTERM (15) is sent to the process. If SIGTERM
    signal is blocked, then the subsequent SIGKILL (9) terminates it.

    timeout
        Integer number of seconds to wait for command completion.
EOF
}

timeout=$1
shift

# $# should be at least 1 (the command to execute), however it may be strictly
# greater than 1 if the command itself has options.
if (($# == 0)); then
    printUsage
    exit 1
fi

(
    # wait $timeout seconds or until the process goes away,
    # polling every second to see if it still exists
    while ((timeout > 0)); do
        sleep 1
        kill -0 $$ || exit 0
        ((timeout -= 1))
    done

    kill -s SIGTERM $$ && kill -0 $$ || exit 0
    sleep 1
    kill -s SIGKILL $$
) 2> /dev/null &

exec "$@"