This should allow you to try out a perl regular expression. You could write a simple perl program to do exactly the same thing, but this allows you to change things slightly to see how the results are affected. Give it a try!
After a (hopefully short) time, you should see the results of the match.
Just in case you don't know, here is a table describing what the different variables mean:
|$&||The text that that matched.|
|$`||The text that occurred before the text that matched.|
|$'||The text that occurred after the text that matched.|
|$n||The text that matched within the nth set of parens. (Count the open parens from left to right to figure out which is the nth set.)|