In this program there's nothing sensitive happening, so I don't see why the code is marked executable to yourself only.
As a matter of sharing tools it seems like a good idea, to me, to place scripts like this in /usr/local/bin so that all users may share them.
Unless there are hardcoded passwords or things that you wish to keep private I failt to see why making scripts 755 is bad in general which the author seems to suggest.
(As for the non-ideomatic Ruby code, I'm not going to cmment on that, as others already have. It's good to see code like this to show newcomers that Ruby can be written however you like).