Commands using wait (7)

  • 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 }

    $COMMAND 2>&1 >/dev/null & WPID=$!; sleep $TIMEOUT && kill $! & KPID=$!; wait $WPID
    keymon · 2010-05-26 11:12:26 2
  • Referring to the original post, if you are using $! then that means the process is a child of the current shell, so you can just use `wait $!`. If you are trying to wait for a process created outside of the current shell, then the loop on `kill -0 $PID` is good; although, you can't get the exit status of the process.

    wait $!
    noahspurrier · 2010-06-07 21:56:36 2
  • A nice way to interrupt a sleep with a signal. Show Sample Output

    sleep 10 & wait $!
    yorkou · 2014-09-25 13:33:51 5
  • If you really _must_ use a loop, this is better than parsing the output of 'ps': PID=$! ;while kill -0 $PID &>/dev/null; do sleep 1; done kill -0 $PID returns 0 if the process still exists; otherwise 1

    bhepple · 2010-01-15 04:03:11 4
  • requires sp-auth installed This command will auto kill sp-sc after vlc is closed, so u wont have to do it manually

    (sp-sc sop:// 8908 10999 &>/dev/null &); sleep 10; wait $(vlc http://localhost:10999); killall sp-sc
    Bonster · 2011-04-06 00:08:38 2
  • This command explains how to manage some asynchronous PID in a global process. The command uses 4 processes in a global process. The asynchronous scripts are simulated by a script more infos :

    sh 1 20 & var1="$!" & sh 2 10 & var2="$!" & sh 3 40 & var3="$!" & sh 4 30 & var4="$!" ; wait $var1 && wait $var2 && wait $var3 && wait $var4
    julnegre · 2012-03-31 10:03:58 3
  • Silent: anywait () { for pid in "$@"; do while kill -0 "$pid" >/dev/null 2>&1; do sleep 0.5; done; done } Prints dots: anywaitd () { for pid in "$@"; do while kill -0 "$pid" >/dev/null 2>&1; do sleep 0.5; echo -n '.'; done; done } Prints process ids: anywaitp () { for pid in "$@"; do while kill -0 "$pid" >/dev/null 2>&1; do sleep 0.5; echo -n $pid' '; done; echo; done } You cannot anywait for other users processes. Show Sample Output

    wait 536; anywait 536; anywaitd 537; anywaitp 5562 5563 5564
    colemar · 2014-10-22 06:31:47 4

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