Execute a command with a timeout

perl -e "alarm 10; exec @ARGV" "somecommand"
In this example the command "somecommand" will be executed and sent a SIGALARM signal if it runs for more than 10 seconds. It uses the perl alarm function. It's not 100% accurate on timing, but close enough. I found this really useful when executing scripts and commands that I knew might hang E.g. ones that connect to services that might not be running. Importantly this can be used within a sequential script. The command will not release control until either the command completes or the timeout is hit.
Sample Output
$ perl -e "alarm 10; exec @ARGV" "sleep 2; echo Hello"
Hello
$ perl -e "alarm 10; exec @ARGV" "sleep 20; echo Hello"
Alarm clock

5
By: jgc
2009-09-23 12:03:55

7 Alternatives + Submit Alt


  • 41
    timeout 5s COMMAND
    kev · 2011-11-19 06:14:33 2

  • 23
    timeout 10 sleep 11
    syssyphus · 2009-09-23 14:59:40 7
  • or "Execute a command with a timeout" Run a command in background, sleep 10 seconds, kill it. ! is the process id of the most recently executed background command. You can test it with: find /& sleep10; kill $!


    6
    very_long_command& sleep 10; kill $!
    dooblem · 2010-04-29 20:43:13 1
  • I like much more the perl solution, but without using perl. It launches a backgroup process that will kill the command if it lasts too much. A bigger function: check_with_timeout() { [ "$DEBUG" ] && set -x COMMAND=$1 TIMEOUT=$2 RET=0 # Launch command in backgroup [ ! "$DEBUG" ] && exec 6>&2 # Link file descriptor #6 with stderr. [ ! "$DEBUG" ] && exec 2> /dev/null # Send stderr to null (avoid the Terminated messages) $COMMAND 2>&1 >/dev/null & COMMAND_PID=$! [ "$DEBUG" ] && echo "Background command pid $COMMAND_PID, parent pid $$" # Timer that will kill the command if timesout sleep $TIMEOUT && ps -p $COMMAND_PID -o pid,ppid |grep $$ | awk '{print $1}' | xargs kill & KILLER_PID=$! [ "$DEBUG" ] && echo "Killer command pid $KILLER_PID, parent pid $$" wait $COMMAND_PID RET=$? # Kill the killer timer [ "$DEBUG" ] && ps -e -o pid,ppid |grep $KILLER_PID | awk '{print $1}' | xargs echo "Killing processes: " ps -e -o pid,ppid |grep -v PID | grep $KILLER_PID | awk '{print $1}' | xargs kill wait sleep 1 [ ! "$DEBUG" ] && exec 2>&6 6>&- # Restore stderr and close file descriptor #6. return $RET }


    4
    $COMMAND 2>&1 >/dev/null & WPID=$!; sleep $TIMEOUT && kill $! & KPID=$!; wait $WPID
    keymon · 2010-05-26 11:12:26 0
  • A timeout is great, but what if the command is taking longer than expected because it's hung up or ran into some other problem? That's where the -k option comes in. Run "some_command" and timeout after 30s. If the command is still running after 1 minute, it will receive a kill signal.


    2
    timeout -k 1m 30s some_command
    tlemerond · 2012-03-27 18:06:18 0

What Others Think

There's also a ?timeout? command (in the timeout package on Debian/Ubuntu) timeout -15 10 somecommand
hfs · 524 weeks and 5 days ago
The problem with the second alternative (background/sleep/kill/foreground is that you have to wait for the full duration of the timeout regardless of how long the command takes to run. In the perl alarm version you will only wait for as long as the command takes to run *unless* it takes longer than the timeout.
jgc · 524 weeks and 5 days ago
OK, timeout is way cooler! Unfortunately at work I'm running on vanilla RHEL, but I like and will use at home :o)
jgc · 522 weeks and 3 days ago
for windows? i want to run .exe with time limit. is there any help?
Aadish26 · 395 weeks ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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