Rather than positively matching against empty lines, why don't you match negatively for non-whitespace characters? 

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

my $tests = '% only 1 profile is allowed

';

my $regex = '\S';
if($tests !~ qr{$regex}ms) {
  print "$tests\n REGEX MATCHED\n";
} else {
  print "$tests\n FAILED!\n";
}

[download]

You could also dynamically build your regular expression based upon the string itself:

my $regex = '^\n{' . $tests =~ tr/\n/\n/ . '}';

If neither of these meet spec, I'd appreciate a more thorough description of what you mean by "maintain this multiline match regex format". I sense this is an XY Problem.

In reply to Re: Multiline match for empty string by kennethk
in thread Multiline match for empty string by josh803316

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