use strict;
my $str = 'Massas23#
Mas23#';
my $regex = qr/^(?!.*[a-z]{3})(?=.*[\d])(?=.*[A-Z])(?=.*[a-z]{2})(?=.*[@#$])[\w\d@#$]{6,12}$/mp;
my $subst = '';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html