Q&A

Q1: What's the difference between m// and just //?
A1: Nothing, really. The m is optional, unless you're using a different character for the pattern delimiter. They both do the same thing.
Q2:Alternation produces a logical OR situation in the pattern. How do I do a logical AND?
A2: The easiest way is simply to use multiple patterns and the && or and operators, like this: 
/pat1/ && /pat2/;

If you know the order in which the two patterns will appear, you can just do something like this:

/pat1.*pat2/

Q3:I have a pattern that searches for numbers: /d*/. It matches for numbers, all right, but it also matches for all other strings. What am I doing wrong?
A3: You're using * when you mean +. Remember that * means “zero or more instances.” That means if your string has no numbers whatsoever, it'll still match—you've got zero instances. + is used for at least one instance.
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