use strict;
my $str = 'quanity*price/2+tax
quanity*price/2
quanity , *price/2+tax
quanity - *price,/2
quanity -, -- , *price,/2
quantity - 3 //,,/price';
my $regex = qr~[\s,]*[-*/+\d]+~mp;
my $subst = '\\n';
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