use strict;
my $str = 'shoot_0001.jpg
shoot_0002.jpg
shoot_0003.jpg
shoot_0004.jpg
shoot_0005.jpg
shoot_0006.jpg
shoot_0007.jpg
shoot_0008.jpg
shoot_0009.jpg
shoot_0010.jpg';
my $regex = qr/^/mp;
my $subst = 'title_';
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