Any Perl Guru Or Less Newbie Than Me?

[lubox.com]

Hello,

 

I never ever programmed in perl before but for the last few days, I have been trying to create a small script to check if an app is ruuning and if it's not to run it. And I will call this script in a cron every 5mins.

 

>#!/usr/bin/perl
$cmd="ps -A | grep xmms | grep -v grep";
$output=qx/$cmd/;
if ($output!=~m/$xmms/) {
qx/xmms/;
}

 

The problem seem to come from the beginning, as if it was not understanding my first command: ps -A | grep xmms | grep -v grep

 

I asked on a programming ofurm, but noone answered me :/ perhaps I will be more lucky here

 

Ludo

[borfast]

I have no idea about what could be wrong, as I know nothing about PERL.

 

But I do have one question: why the "grep -v grep" command at the end? Won't the output of the script be just the same without it?

[lubox.com]

Good question Raul

 

In fact I created this script in using several scripts find on Google...

I just tried to take off this last part and you are right... it changes nothing! but even without it, it's not working.

 

One small mistake at the time, I'm sure I will get this damned script working! lol

 

Ludo

[dmohs]

The following line is suspicious:

>if ($output!=~m/$xmms/)

 

Is it your intention to have this if statement be true if "xmms" is not found in the output? If so, it would need to be:

 

>if ($output !~ m/xmms/)

 

The proper syntax for "match if not" is "!~". In the above, $xmms will match the variable $xmms which is not defined as you have presented your script.

[TCH-Bruce]

Hi Ludo,

 

I'm curious as to why you want to write it in Perl? Couldn't you just do it with a shell script? I'm assuming you are wanting to run this on your own machine, right? Something like this:

 

CMD=`ps -A | grep xmms`

if [ ${CMD} = "" ]

then

execute the command

fi

Edited June 5, 2004 by TCH-Bruce