parsing ps -ax output and killing processes

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• 8 Comments
• • 
  • "Rob" <rob.unix-linux.itags.org.nospam.com> wrote in message news:ctlQd.28350$uc.1458.unix-linux.itags.org.trnddc09...

    > After the success of writing my first script yesterday (thanks guys!) I'm

    > motivated to move on to something more complex today.

    > How would I go about doing something like a

    > ps -ax | grep xxxx

    > and then killing any processes listed (except for the one running the

    > command of course). There may not be any processes, I

    > was thinking to detect that I could write out to a file and check the file

    > size, but I guess that doesn't really help me if there are

    > any processes listed. Basically I run a shutdown script which doesn't

    > always work, then need to verify that the script did work

    > by seeing if processes are still running and manually killing them if they

    > arent.

    >

    im reading the awk man pages, it looks like that's probably what

    i should be looking at but talk about confusing :). oh, this is for

    bash on redhat if that makes a difference.

    im playing with something along the lines of

    awk -F: '{ print $1 }' | ps -ax | grep xxx

    to at least output the process numbers, but it doesn't return me to the

    shell and i'm not sure what to do from there anyway :)

    #1; Wed, 30 Apr 2008 14:13:00 GMT
• • 
  • "Rob" <rob.unix-linux.itags.org.nospam.com> wrote in message news:yMlQd.28360$uc.5215.unix-linux.itags.org.trnddc09...

    > "Rob" <rob.unix-linux.itags.org.nospam.com> wrote in message

    > news:ctlQd.28350$uc.1458.unix-linux.itags.org.trnddc09...

    > im reading the awk man pages, it looks like that's probably what

    > i should be looking at but talk about confusing :). oh, this is for

    > bash on redhat if that makes a difference.

    > im playing with something along the lines of

    > awk -F: '{ print $1 }' | ps -ax | grep xxx

    >

    > to at least output the process numbers, but it doesn't return me to the

    > shell and i'm not sure what to do from there anyway :)

    >

    it just occured to me the above example isn't doing anything more than

    the ps -ax | grep xxx is :) :). oops!

    #2; Wed, 30 Apr 2008 14:14:00 GMT
• • 
  • "Rob" <rob.unix-linux.itags.org.nospam.com> wrote in message

    news:lOlQd.28361$uc.27028.unix-linux.itags.org.trnddc09...

    > "Rob" <rob.unix-linux.itags.org.nospam.com> wrote in message

    > news:yMlQd.28360$uc.5215.unix-linux.itags.org.trnddc09...

    > it just occured to me the above example isn't doing anything more than

    > the ps -ax | grep xxx is :) :). oops!

    >

    new direction ... i just found pgrep and pkill commands :).

    #3; Wed, 30 Apr 2008 14:15:00 GMT
• • 
  • On Tue, 15 Feb 2005 11:58:00 +0000, Rob wrote:

    > After the success of writing my first script yesterday (thanks guys!) I'm

    > motivated to move on to something more complex today. How would I go about

    > doing something like a

    > ps -ax | grep xxxx

    > and then killing any processes listed (except for the one running the

    > command of course). There may not be any processes, I was thinking to

    > detect that I could write out to a file and check the file size, but I

    > guess that doesn't really help me if there are any processes listed.

    > Basically I run a shutdown script which doesn't always work, then need to

    > verify that the script did work by seeing if processes are still running

    > and manually killing them if they arent.

    It is more normal to use 'awk' here, rather than grep, as you need to not

    only select particular lines, you then need to manipulate them.

    Awk is pretty easy to use, and has all the searching of grep built in.

    However since this is your second script, let us proceed in small steps.

    You already know you want to do something like 'ps -ax | grep something'

    and then manipulate the result. If there is nothing left then do nothing,

    otherwise run kill on it. The 'test' command (also known as '[') can tell

    if a variable is null or not, and it can also test to see if a file is

    empty. Modern shells such as ksh, bash, zsh have a syntax element called

    '[[' which handles things a little better.

    So one thing you could do is

    tokill=$(ps -ax | grep something | extract_just_the_first_column)

    if [[ -n $tokill ]]

    then

    kill $tokill

    fi

    A command for extract_just_the_first_column is

    awk '{print $1}'

    You also say you don't want to kill off the commands doing the killing. A

    way of doing this is to use 'grep -v pattern' which selects the lines

    which do not match. putting this together

    tokill=$(ps -ax | grep something | grep -v grep | awk '{print $1}')

    If you want the "something" to be fixed, then you have it. Otherwise you

    can use the positional parameters.

    #!/bin/sh

    tokill=$(ps -ax | grep -- "$1" | grep -v grep | awk '{print $1}')

    if [[ -n $tokill ]]

    then

    kill $tokill

    fi

    #4; Wed, 30 Apr 2008 14:16:00 GMT
• • 
  • In article <U6mQd.6906$m31.86596.unix-linux.itags.org.typhoon.sonic.net>,

    Icarus Sparry <usenet.unix-linux.itags.org.icarus.freeuk.com> wrote:

    >tokill=$(ps -ax | grep -- "$1" | grep -v grep | awk '{print $1}')

    >if [[ -n $tokill ]]

    >then

    > kill $tokill

    >fi

    The first line could simplified as

    tokill=$(ps -ax | awk "/[${1:0:1}]${1:1}/ { print \$1 }")

    --

    For low fair air travel, take Independence Air - http://www.flyi.com/.

    Michael Wang * http://www.unixlabplus.com/ * mwang.unix-linux.itags.org.unixlabplus.com

    #5; Wed, 30 Apr 2008 14:17:00 GMT
• • 
  • <previous content deleted>

    Thanks a TON for that primer, it's a bit confusing to me, but it will come

    to me. I ended up using

    pkill as you probably saw in another of my threads, but what you've shown me

    I can already think

    of a million uses for.

    #6; Wed, 30 Apr 2008 14:18:00 GMT
• • 
  • On Tue, 15 Feb 2005 12:57:10 GMT,

    Michael Wang <mwang.unix-linux.itags.org.unixlabplus.com> wrote:

    > The first line could simplified as

    > tokill=$(ps -ax | awk "/[${1:0:1}]${1:1}/ { print \$1 }")

    "ps axc" would be easier to parse as the fifth field will then be the

    complete basename of the program name without arguments. Similar "ps -e"

    for SystemV flavour.

    ps axc |awk "\$5 == \"$1\" { print \$1}"

    ps -e |awk "\$4 == \"$1\" { print \$1}"

    As long as the process isn't selected based on arguments there would be

    no reason for ps to provide this information.

    Villy

    #7; Wed, 30 Apr 2008 14:19:00 GMT
• • 
  • On Tue, 15 Feb 2005 18:23:01 GMT,

    Michael Wang <mwang.unix-linux.itags.org.unixlabplus.com> wrote:

    > In article <slrnd140o8.294.vek.unix-linux.itags.org.station02.ohout.pharmapartners.nl>,

    > Villy Kruse <nobody> wrote:

    > If $1 is the command, then

    > ps -e |awk "/[0-9] $1/ { print \$1 }"

    > would do.

    Or use pure shell:

    ps -e | while read PID TTY TIME CMD

    do

    case $CMD in

    $1) echo $PID ;;

    *) ;;

    esac

    done

    ps axc | while read PID TTY STAT TIME COMMAND

    do

    case $COMMAND in

    $1) echo $PID ;;

    *) ;;

    esac

    done

    Villy

    #8; Wed, 30 Apr 2008 14:20:00 GMT