my $test = "asdflkjeroiuasdflkjabcdeawerij2lkjasdf";
my $string = join '', (a..z);
my $match = 0;
my $string = "$string ";  # add one junk char...
do {
   $string = substr( $string, 0, -2 );
   $match = $test =~ $string;
} while ( !$match || !$string );
print $match ? "success with $string!\n" : "failure\n";