Finding the PID of zenity in a perl script.

HappyTimeHarry has asked for the wisdom of the Perl Monks concerning the following question:

I have a simple but ugly script that reminds me of things I need help remembering.

#!/usr/bin/perl -w
#reminder.plx
use strict;
use Data::Dumper;

$/ = "#-";

open(INFILE, "/foo/reminder.txt") or die "Can't open reminders.txt: $!
+";
my @reminders = <INFILE>;
my $random = rand(@reminders);
my $reminder = $reminders[$random];
$reminder =~ s/\d\. //g;

chomp $reminder;

my $pid; # From here on down is the part I don't like, although it doe
+s do what I want it to do.

defined ($pid = fork()) or die $!;
if ($pid==0)
{

$pid and last;
exec ("/usr/bin/zenity --display=:0.0 --info --title='Reminder' --text
+='$reminder' &") or die "Something went wrong:$!";
}
my $retval;
sleep 100;
$pid++;
kill 15, $pid;
[download]

The part that bothers me is the bit that finds the pid of zenity and kills it. I couldn't figure out/find a better way of finding the pid. The method I used seems to find the pid just before (numerically speaking) my zenity dialog, so I used $pid++ to get the pid I wanted, but this seems dangerous for reasons you probably understand better than I do. I'd appreciate any helpful suggestions on how to improve this script, especially the part I've just described.

I'm using Ubuntu linux btw.

Comment on Finding the PID of zenity in a perl script. Download Code

Replies are listed 'Best First'.
Re: Finding the PID of zenity in a perl script. by Tanktalus (Canon) on Nov 11, 2010 at 00:05 UTC
You have to stop using & in your exec, since that creates yet another pid. `exec ('/usr/bin/zenity', '--display=:0.0', '--info', '--title=Reminder +', '--text=' . $reminder) or die ...` [download] I suspect that your $pid++ is assuming that nothing else gets launched between your fork/exec and the shell's parsing and fork/exec of zenity. That all said: formatting! And try Proc::Fork or something to simplify your child/parent handling.	[reply] [d/l]
Re^2: Finding the PID of zenity in a perl script. by HappyTimeHarry (Initiate) on Nov 11, 2010 at 00:20 UTC
Perfect! Thank you very much. :)	[reply]
Re: Finding the PID of zenity in a perl script. by aquarium (Curate) on Nov 11, 2010 at 03:53 UTC
i seem to be always taking the knife to the fork..so to speak. but it seems as overkill to fork and kill a process, just to get some output in X and time out. you could instead use a little wrapper called xmessage around xdialog, or use xdialog directly. the hardest line to type correctly is: stty erase ^H	[reply]