Fletch is right -- use File::Basename -- but in the more general case of finding the last token in a string, that regex ought to work:

#!/usr/local/bin/perl
use strict;

my $string = '/one/two and three/and four / and five';
if ($string =~ /.*\/(.*?)$/) {
  print "Last token: $1\n";
}
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Or you could always split on your token separator and grab the last element in the resulting array.