[ILUG] Script Query

[Ciaran Johnston]

On Sunday 06 April 2008 12:44:54 Colm Buckley wrote:
> On Sun, Apr 6, 2008 at 12:29 PM, Ian <ianhoweire at gmail.com> wrote:
<snip>
> then i want to have another script that can kill the process.
>
> > I presume i am only able to kill the process using the pid using the
> > format
> > 'kill 1234'
> > I can use the following line to copy the pid to a file
> >
> > ps -e | grep firefox-bin | cut -d ' ' -f2 > ~/processID
> >
> > how then can i pass the entry in processID to the kill command.
> > Or if there is another way to do this i''m all ears.
>
> killall firefox-bin
>
> Or, if you really do want to do it using the above:
>
> kill `ps -e | grep firefox-bin | cut -d ' ' -f2`
>
> Note the backticks.  Most modern shells will also allow $(), so:
>
> kill $(ps -e | grep firefox-bin | cut -d ' ' -f2)

this will only work for PIDs between 1000 and 9999 - the output of ps -e is 
formatted with the integer value right-justified (presumably with a "%5d" in 
a printf statement):

    1
   10
  100
 1000
10000

cut simply splits a string according to the delimiter you give, and returns 
the parts you request, so
$(ps -e | grep firefox-bin | cut -d' ' -f2)
will return "" for numbers less than 1000, and either the terminal  - 
e.g. "pts/1" - or "?" for numbers greater than 9999.

You should use awk instead in this situation:

kill $(ps -e | grep firefox-bin | awk '{print $1}')

>
> will also work.  killall is easier, though.  Note : I believe the Linux
> killall has different semantics from the Unix one; if you run killall on
> (eg:) a Solaris system, it will send a signal to all processes, not just
> the named ones.

"pkill" is a likelier candidate here - it works much the same way on Solaris 
and Linux. It can also accept a user id in case you don't want to 
get "Operation not permitted" error messages if another user is running 
firefox on the same system - or worse, kill the processes of other users if 
you happen to be running your script as root.

pkill -u $USER firefox-bin

Note that sending kill signals to firefox in this way will result in an error 
message about your last session closing unexpectedly next time you start it - 
rather silly behaviour from a web browser, I reckon. Does anyone know how to 
turn this behaviour off?

/Ciaran.