This may or may not be good in your case...

#!/usr/bin/perl -l

$x = "dog 789 cat dog dog bird cat wonder dog frog cat";

@finds = ($x =~ /((?:dog)(?:.*?)(?:cat))/g);

$y = reverse $x;
@finds2 = ($y =~ /((?:tac)(?:.*?)(?:god))/g);

print for @finds;
print "-----";
print scalar reverse for reverse @finds2;
[download]

Ouptuts:

dog 789 cat
dog dog bird cat
dog frog cat
-----
dog 789 cat
dog bird cat
dog frog cat
[download]

It's a nice technique to know, anyway. (The credit goes to japhy for it.)