91

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?

6
  • 4
    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) Jul 19 '12 at 22:12
  • 1
    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. 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. Jul 20 '12 at 0:31
142

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.

7
  • 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#*:*:}%%=*}. Jan 28 '16 at 10:06
  • 3
    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
24

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

jobs -p | xargs kill
5
  • 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 Jun 8 '17 at 12:23
  • This works great on CentOS 6 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
  • 2
    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. Jun 10 '19 at 11:09
6

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
  • 3
    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
  • 4
    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. Jul 6 '19 at 2:56
4

@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.

1
  • Finally, this works and sends kill signal to all background process groups, sending it to all background processes. Parsing jobs output to find out jobs numbers, then passing job numbers to kill for jobspec is the way to go. Can be shortened a bit to for j in $(jobs | awk '{gsub("[^0-9]","",$1);print $1}'); do kill %$j; done. Thank you.
    – KamilCuk
    Apr 16 at 17:43
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.

5
  • 1
    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. 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? Jan 27 '20 at 15:47
  • 1
    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
3

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
  • 2
    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

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.

0

The accepted answer by @jw013 works in most situations, except when a job has background jobs since only the group leader is killed. (@pizdelect identified this limitation in this comment.)

@pizdelect also pointed out that kill accepts negative PID values to choose the whole process group in this comment.

Furthermore, one might not want to kill Stopped jobs, hence jobs -r might be useful.

Combining all these elements, here's a solution that kills all running jobs, including background jobs:

for i in $(jobs -rp); do kill -- "-$i"; done

Here's a solution that kills all jobs, including background jobs:

for i in $(jobs -p); do kill -- "-$i"; done

-1

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

2
  • 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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