"...is there any compelling reason not to do a "local $_;" at the beginning of every subroutine?"
Yes, doesn't fix the problem. Any time you call a function, subroutine or method it could blow away $_. And you will never have control of other peoples code so if you rely on $_ not being hosed you'll eventually get burnt.
And by the same token, if you're a module author, you have no control over your user's code, and if you're stomping on $_, eventually one of them will be burned by it.

So if you don't want to burn your users, you should always localize $_.

In reply to Re^4: cpan install($_) doesn't work in loop, but normal lexical var does by doom
in thread cpan install($_) doesn't work in loop, but normal lexical var does by tphyahoo

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