15

Currently I use line like this in my sh script file:

kill `ps aux | grep -F 'myServer' | grep -v -F 'grep' | awk '{ print $2 }'` 

But I wonder how to call it only if process (myServer here) is running?

  • it's impossible to call kill only when the process is running, because there is a race condition between the test and the invocation of kill (it's possible the process stopped for another reason in that short time). You should use pkill or killall which do exactly the same as what you try to do, but with less to type (and probably some other advantages too). – JanC May 10 '16 at 12:26
21

I usually just use pgrep and pkill

if pgrep myServer; then pkill myServer; fi
| improve this answer | |
  • 7
    Why not pkill myServer or killall -q myServer? There's no downside to attempting to kill inexistent processes. – David Foerster Oct 3 '14 at 15:57
  • 13
    It will not exit 0 if there is no process to kill, so it could break scripts. – boutch55555 Oct 6 '14 at 15:00
  • 6
    Append || true then. – David Foerster Oct 6 '14 at 15:01
  • True, but you won't have the flexibility to add a else to inform you the process was already dead. – boutch55555 Oct 6 '14 at 16:57
  • What about if ! killall -q myServer; then echo ERROR; fi? – David Foerster Oct 6 '14 at 17:07
9

You could kill processes by name using pkill or killall, check their man pages.

| improve this answer | |
  • yes, unlike kill, this kills only if process is running. For example pkill -u myuser -f myprocess\.[0-9]+ – Chase T. Jun 26 '17 at 18:50
6

A bit of a different approach would be something like this:

killall PROCESS || echo "Process was not running."

This will avoid the 1 Error-Code returned from the killall command, if the process did not exist. The echo part will only come into action, if killall returns 1, while itself will return 0 (success).

| improve this answer | |
  • 5
    Using killall -q is better – Anwar Jun 27 '17 at 15:51
  • 1
    Warning, killall -q isn't supported on all unix flavors, macOS Catalina still doesn't have it. – tresf Oct 4 '19 at 14:36
  • 1
    @tresf my ubuntu distribution doesn't have it either – FooBar Sep 25 at 22:00
1

Check if the process exist with pidof. If it does, kill it:

(! pidof process_name) || sudo kill -9 $(pidof process_name)

Exit code is always 0 after executing the above command.

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0

try using:

sudo kill `pidof process_name`

where process_name is the name of the process you want to kill. What's great about this is that pidof will list the pid's of all processes matching the given name. Since kill accepts multiple pid's, it will kill of all of them in a single whim.

Let me know if this helps.

| improve this answer | |
  • What if list is empty? (my main point was not to call kill at all if possible) – myWallJSON Jan 31 '12 at 12:44
  • 1
    If the list is empty, kill will return an error code 1 and not kill anything. It would be the equivalent as trying to call kill with no arguments. You could add an if statement that first checks if pidof returns an empty list. If it does not return an empty list, call kill `pidof process_name. If it does return an empty list, skip the kill call. – amandion Jan 31 '12 at 12:59
0

Small Script I have created with R&D. I hope you will like it

#!/bin/bash

echo " Enter the process name:"
read $proc_name
if pgrep $proc_name
then
echo " $proc_name running "
pkill $proc_name
echo "$proc_name  got killed"
else
echo " $proc_name is not running/stopped "
fi

save it with some name like script.sh then

chmod +x script.sh
./script.sh

Then give your process name.

Note: I have tried many times with this and its fine.

| improve this answer | |
  • May I know whats wrong with this script and -ve vote needs an explanation please. – rɑːdʒɑ Oct 5 '14 at 5:33
  • Nothing wrong with this script... +1 – WinEunuuchs2Unix Nov 13 '16 at 1:26
0

Use pkill with option -f

pkill -f myServer

Option -f is the pattern that is normally matched against the process name.

| improve this answer | |
-1

I would use:

ps x --no-header -o pid,cmd | awk '!/awk/&&/myServer/{print $1}' | xargs -r kill

The xargs -r tells to run kill only if there is input. The ps --no-header -eo pid,cmd gets the output into a better format for parsing.

| improve this answer | |

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