use strict;
my $str = 'A product description with 12 1/2" in it.
Product description with 19 3/4" x 19 5/8" in it.';
my $regex = qr/\d*\s?\d+\/\d+"*\s*(in|")\sx\s\d*\s?\d+\/\d+"*\s*(in|")(*SKIP)(*FAIL)|\d*\s?\d+\/\d+"*\s*(in|")/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