use strict;
use warnings;


my $data = 'blabla;tag1=12345;blabla;';
# my $data = 'blabla;tag1=12345;blabla;tag2=99999';

# get tag1 value
$data =~ m/tag1=(\d+)/g;
my $tag1 = $1;

# get tag2 value
$data =~ m/tag2=(\d+)/g;
my $tag2 = $1;

print "tag1 = $tag1\n";
print "tag2 = $tag2\n";

##</code><code>##

tag1 = 12345
tag2 = 12345