Sams Teach Yourself Perl in 21 Days, Second Edition

A Few More Patterns

To finish up—because we have a little space left over today—I'd like to tuck a couple more patterns into your regular expressions repertoire, so that you can keep building on what you've learned (and so that I can use them in the last example you're about to work through).

So far you've learned about patterns with individual characters:

/abc/

Patterns with digits:

/\d/

And patterns with nondigits:

/\D/

Here's another one: \s is a whitespace character. Whitespace in Perl is a space, a tab, a newline, a carriage return, or a formfeed. The \s pattern counts as any of these. Just as with \d, however, \s only means a single whitespace character, so the pattern /\s/ will match one and only one space, tab, newline, and so on. ...