In general, with Perl, do not mess with $1 or $2, etc variables. There are exceptions, this is not one of them.

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

my @data;

while (<DATA>)
{
   next if ( /^\s*$/ ); #skip blank lines
   
   # easy way to to get numbers after "="
   
   my ($tag1, $tag2, $extra) = /\s*=\s*(\d+)/g;
   
   #skip malformed lines..
   #must be 2 number tokens after "="
   
   if (defined $tag1 and defined $tag2 and not
       defined $extra)
   {
      print "$tag1 \t$tag2\n";
   }
   else
   {
      print "Bad Line:$_";
   }
}

=prints
12345   99999
Bad Line:blabla;tag1=12345;blabla
Bad Line:awdrfaf; tag2 = 122345;
6768    9876
Bad Line:079a8; tag1 =345; tag2 = 895; tag3=3987;
12567   98999
7899    8977
=cut


__DATA__
blabla;tag1=12345;blabla;tag2=99999

blabla;tag1=12345;blabla
awdrfaf; tag2 = 122345;

asdf;tag 1 = 6768;  tag2= 9876;
079a8; tag1 =345; tag2 = 895; tag3=3987;

blabla;tag1 =12567;blabla;tag2= 98999
blabla;tag1= 7899;blabla; tag2 =8977
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