Execute a command with a timeout
$ time alarm 5 telnet 10.10.10.10 Trying 10.10.10.10... Alarm clock real 0m5.004s user 0m0.002s sys 0m0.003s $
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43timeout 5s COMMAND
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23timeout 10 sleep 11
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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 $!6very_long_command& sleep 10; kill $! -
In this example the command "somecommand" will be executed and sent a SIGALARM signal if it runs for more than 10 seconds. It uses the perl alarm function. It's not 100% accurate on timing, but close enough. I found this really useful when executing scripts and commands that I knew might hang E.g. ones that connect to services that might not be running. Importantly this can be used within a sequential script. The command will not release control until either the command completes or the timeout is hit. Show Sample Output
5perl -e "alarm 10; exec @ARGV" "somecommand" -
I like much more the perl solution, but without using perl. It launches a backgroup process that will kill the command if it lasts too much. A bigger function: check_with_timeout() { [ "$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
rahimhh21
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87 weeks and 1 day ago 
Perfecthomepugs
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78 weeks ago 
loanabilly
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63 weeks and 2 days ago 
pugpuppies95
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40 weeks ago 
liltommy
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40 weeks ago 
donperi1
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32 weeks and 2 days 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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