75

Is there a more compact form of killing background jobs than:

for i in {1..5}; do kill %$i; done

Also, {1..5} obviously has a hard-coded magic number in it, how can I make it "N" with N being the right number, without doing a:

$(jobs | wc -l)

I actually use \j in PS1 to get the # of managed jobs, is this equivalent?

  • 3
    kill $(jobs -p) seems easier. – jw013 Jul 19 '12 at 22:00
  • I would prefer to kill jobs individually, if possible. (I might have misunderstood your comment, though) – Robottinosino Jul 19 '12 at 22:12
  • for pid in $(jobs -p); do kill $pid; done? – jw013 Jul 19 '12 at 22:27
  • 3
    @jw013 It's not only easier, it's actually correct (please post it as an answer), unlike a solution based on counting the lines of the output of jobs which only works if the jobs happen to be numbered consecutively. Oh, and “kill jobs individually” is meaningless: passing multiple PIDs to the kill command does exactly the same thing as passing them separately. – Gilles 'SO- stop being evil' Jul 19 '12 at 23:52
  • I was entering the command incorrectly, kill $(jobs -p) words and looks very correct to me too. Ready to accept. – Robottinosino Jul 20 '12 at 0:31
122

To just kill all background jobs managed by bash, do

kill $(jobs -p)

Note that since both jobs and kill are built into bash, you shouldn't run into any errors of the Argument list too long type.

  • 2
    Also for posterity, what bahamat thinks is the way to do it in zsh disqualifies them as any authority on the topic. – peth Mar 8 '13 at 23:46
  • 1
    I feel like I should know this, but how does the '$' work here? – fersarr Jan 8 '15 at 17:21
  • 1
    @fersarr Here you go – jw013 Jan 8 '15 at 21:27
  • @bahamat That doesn't actually work since the PID may be in field 2 or 3 depending on whether the job is one of %+ or %- or not. What works is kill %${(k)^jobdirs}, which is indeed longer; if you need to list the PIDs then you can use the even longer ${${jobstates#*:*:}%%=*}. – Gilles 'SO- stop being evil' Jan 28 '16 at 10:06
  • 1
    This answer is incorrect. This will not kill all the processes from the background jobs, but only the process group leaders. Try with sleep 3333 | sleep 3333 &; after kill $(jobs -p), jobs will still show the background job as running -- only one of the 2 sleep processes will be killed. – pizdelect May 28 '20 at 14:49
22

Use xargs instead of the $(jobs -p) subcommand, because if jobs -p is empty then the kill command will fail.

jobs -p | xargs kill
  • 2
    This has the same exact effect though , it prints the help and exits with code 123 – cat Jun 7 '17 at 20:51
  • 1
    The the command works fine on OSX but doesn't work on Debian – brunocascio Jun 8 '17 at 12:23
  • This works great on CentOS 6 – Janac Meena Nov 13 '18 at 19:19
  • jobs -p | xargs -rn10 kill will do better better if jobs -p does not return any PIDs. Note that -r option is GNU extension. – NarūnasK Feb 1 '19 at 16:27
  • 1
    As mentioned above, the -r is the short format for the --no-run-if-empty GNU extension to xargs which instructs it to not run the command if stdin has no data. – Anthony Geoghegan Jun 10 '19 at 11:09
5

I guess depending on what output jobs -p gives, the solution could be slightly different. In my case

$ jobs -p
[1]  - 96029 running    some job
[2]  + 96111 running    some other job

Therefore, doing the following is no good.

$ jobs -p | xargs kill
kill: illegal process id: [1]

On the other hand, running kill $(jobs -p) does work but entails a lot of error messages, since the non-PID strings get passed to kill as well.

Therefore, my solution is to grep the PID first and then use xargs, as follows:

$ jobs -p | grep -o -E '\s\d+\s' | xargs kill
  • 2
    What shell are you using? What does echo $0 show? What does help jobs show? The output illustrated is not POSIX-compliant; any implementation of jobs should have a -p option with the intended behavior. – Wildcard Jul 5 '19 at 22:16
  • 2
    Thanks for pointing this out. I am using zsh, and that is the reason for the strange output. I switched to bash and jobs -p did only output PID. I've just learned that zsh is not completely POSIX-compliant. – Fanchen Bao Jul 6 '19 at 2:56
3

I prefer to check if there's any jobs that exist before killing them - this way the script won't fail if there's nothing running.

It's also shorter to type. Throw this in your .bash_profile:

function killjobs () {
    JOBS="$(jobs -p)";
    if [ -n "${JOBS}" ]; then;
        kill -KILL ${JOBS};
    fi
}

Then run:

killjobs

To kill any jobs running.

  • Why do you use the KILL signal? If you use Bash, you could use -r with jobs to list only running jobs. – jarno Jan 25 '20 at 20:41
  • Because the question asker said to 'kill all background jobs' not 'terminate all background jobs'. I appreciate that it's possible they may have not been speaking exactly though, especially as they send a TERM in their example. – mikemaccana Jan 27 '20 at 15:29
  • You should use KILL signal usually only, if nothing else works, because the processes can not do any cleanup tasks with the signal. – jarno Jan 27 '20 at 15:35
  • @jarno Yes, I understand. The question is does the question asker? – mikemaccana Jan 27 '20 at 15:47
  • It is still possible that some of the processes are terminated when running the function before calling kill. – jarno Jan 28 '20 at 12:33
1

I have several backgrounded compound commands I want to terminate gracefully, by sending SIGINT to each process, on macOS. None of the other solutions worked properly for that, so I came up with this:

jobs -p | xargs -n1 pkill -SIGINT -g

jobs -p lists background processes started by the current shell.

xargs -n1 executes pkill once for each job.

pkill -SIGINT -g sends SIGINT (same as ctrl+c) to all processes in the process group.

1

In bash and zsh I would use something like this (after considering the comment from pizdelect about the process group):

jobs -p | extract_pids | xargs --no-run-if-empty kill -TERM -- || true

where

extract_pids() {
    awk '{
        if (NF == 1) { print -$1 }
        else if (NF > 1) {
            if ($2 == "+" || $2 == "-") { print -$3 }
            else { print -$2 }
        }
    }'
}

As far as I tested jobs -p returns the PIDs in bash, f.i.:

$ jobs -p
41659

but can have these formats in zsh, f.i.:

$ jobs -p
[1]    206 running    sleep 10
[2]  - 208 running    sleep 10
[3]  + 210 running    sleep 10

extract_pids tries to handle these (4) cases.

Note: checking the processes with jobs -p can return PIDs, which are already gone at the time xargs kill is invoked, so we ignore errors with a trailing || true.

  • 1
    That will only kill the job (process group) leaders, not the background jobs. Try with sleep 3333 | sleep 3333 & -- only one of the sleep processes will be killed and jobs will still show the background job as running. You should negate the pids if you want to kill entire jobs, not just job leaders. Yes this is a problem with the other answers, too. – pizdelect May 28 '20 at 14:34
1

@pizdelect point is what brought me here. Jobs spawned using pipes have multiple pids. jobs -p is only going to provide the first.

for j in $(jobs | awk '{gsub("[^0-9]","",$1);printf "%%%s\n", $1}');do kill $j;done

If you want to get them all, you have to use the job ID.

0

Seems like jobs -p | xargs kill does the job, however it produces some unwanted output piped to kill. Here I am grouping output of jobs -p by having/not having + or - character

function killjobs() {
    JOBS=$(jobs -p)
    echo $JOBS | grep -v "+\|-"| awk '{print $2}' | xargs kill -9
    echo $JOBS | grep "+\|-"| awk '{print $3}' | xargs kill -9
}

And later you can just call killjobs

  • Which shell do you run so that you get those +/- in $(jobs -p)? – jarno Jan 25 '20 at 20:32
  • zsh is a very common shell that has a non-POSIX-compliant jobs output, which does include plus and minus. – AndrewF Sep 10 '20 at 21:59

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