Let's look at the second rule now - what exactly does this mean?
It means that when something being affected by a quantifier can match,
it matches as much as it possibly can.
Here's a simple example. In the following text:
This is a boring sentence
the regex:
This?
will match:
This
Note that the "?" quantifer allows the regex portion it modifies (in this case
the literal character "s") to match zero or one times - or, if you like, it
makes the "s" character optional in this regex. So, in theory, the regex
could have matched just:
Thi
However, this isn't what happens, because the "?" quantifier is greedy, and
it matches the maximum possible amount it can.
This is not to say that the "?" can't match zero number of times - it can,
but it will only do this if matching would mean that the regex would be unsuccessful.