Don't know Net::NNTPClient, but...

The first two snippets are equivalent (the second one may occupy more memory since it build an array of the msgids)

In the third one, you are saying: for each number between $first and $last, if that number is undef or the empty string...

Since no number passes the test, @messages will not be altered (assuming that that @testlist should be @messages)

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        dakkar - Mobilis in mobile