No, everything in the regex must match, not just the first part of it, and the part in the middle with the (one|two|three) must match too.

The thing that you must remember is that regexes can backtrack -- if they get to the end of the string without having matched yet, they can go back a few letters and try again.

So the .* part will first try to match the entire string, because it is greedy. Then the middle part (one|two|three) must match, but there is nothing left in the string, and we must backtrack and try again. First we try going one letter back, then two, and eventually we either find the match or we backtrack all the way to the start and then there is no match.

The reason that most people say you shouldn't use .* is because it can match nothing (or everything) so matching just .* is pointless because it will match everything (including nothing) However, if you were looking for "hi" some ammount of text and then "there" you could use:

$line =~ /hi.*there/;
[download]

and it would match. Of course it's greedy and might not be exactly what you wanted but there are times when it is needed. However, it is overused a lot and usually something better can be used.

To answer your question though, /.* doesn't grab everything because it has required stuff after that. If you try and match /.*some text/ It has to find "some text" or it will fail. However, if you try and match something like: /.*\d?/ it could match nothing since the \d is optional.

The \s? at the end is useless though (unless $& is used).