This works for firefox. It will open firefox if not already running. If running, it will open a new tab or window.

#!/usr/bin/perl
use warnings;
use strict;

my $linkurl = 'http://google.com';
#my $file = 'my_local_page.html';

#my $command = "firefox $file";
# if(fork() == 0){ exec ($command) }  #works

#external url
my $command = "firefox $linkurl";
if(fork() == 0){ exec ($command) }
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