Re: using regular expression to extract subset from a line

[DamnDirtyApe]

I'll leave the analysis of what you've got to someone who's better at regexps than I, but if you're simply looking to extract the argument from a space-delimited string that ends in "makefile", try something simpler like this:

#! /usr/bin/perl -w
use strict;

my $old_str = 'make -r -f ..\../tools/cell/makefile cell.lib';
my $new_str = ( $old_str =~ /\s+(\S*makefile)/ )[0];
print "New string: $new_str$/";

__END__

HTH

Update: You could do this with split and grep also:

my $new_str = ( grep { /makefile$/ } split /\s+/, $old_str )[0];