grep'ping the ps output....

[Louis J. LeBlanc]

On Mon, December 12, 2005 11:04 am, Eric Schuele wrote:
> Hello,
>
> I am sure this is quite trivial, but...
>
> I have need to determine if an app (firefox, or anything really) is
> already running before I perform some action.  So I grep the ps output.
>   However sometimes (many times) that which I'm searching for is present
> in the output because I am presently grep'ing for it.  But it is not
> always there.  It seems to be a bit inconsistent. (See below).
>
> I was wondering if someone could explain why it is sometimes there and
> not other times.  And how I should correctly go about detecting if the
> process is running before I perform my action.
>
> Thanks,
> Eric
>
>
> %ps | grep firefox^M^M
>    703  v0  I      0:00.00 /bin/sh /usr/X11R6/bin/firefox^M
>    722  v0  I      0:00.00 /bin/sh /usr/X11R6/lib/firefox/run-mozilla.sh
> /usr/X1^
> M
>    734  v0  S      0:10.92 /usr/X11R6/lib/firefox/firefox-bin^M
> %ps | grep firefox^M^M
>    703  v0  I      0:00.00 /bin/sh /usr/X11R6/bin/firefox^M
>    722  v0  I      0:00.00 /bin/sh /usr/X11R6/lib/firefox/run-mozilla.sh
> /usr/X1^
> M
>    734  v0  S      0:10.92 /usr/X11R6/lib/firefox/firefox-bin^M
>   1230  p1  RV     0:00.00 grep firefox (csh)^M
> <SNIP>

You probably want something more like this:

ps | grep firefox-bin | grep -v grep

piping the first output set back into grep -v grep filters out any entry
that matches the token "grep", pulling out the one you're trying to avoid.

HTH
Lou
-- 
Louis LeBlanc                 FreeBSD at keyslapper.net
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