The reason this, and many other variables are persistent, is that they're "global special variables", which is to say, Main::variable_name has some magic to it (in this case, Main::$3 is the third captured match). The upshot is, once $3 gets set by a match, it can't go away by going out of scope (Ignore that, it was wrong. Match variables are implicitly dynamically scoped for extra magic, as ig points out in the reply below.) perlvar could provide some further enlightenment on the subject (or might bury you in details). As the other answers have said, you need to test that the match succeeded before you use the result.

In reply to Re: Problem with regexp or saved match variable. by ssandv
in thread Problem with regexp or saved match variable. by steve077

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