7.9. Useful Escape Sequences

Perl has several escape sequences which are specific to regular expressions. Here is a list of some of the more useful ones:

• \w - matches a word character, equivalent to [A-Za-z_]. The corresponding sequence - \W matches a non-word character.
• \s - matches a whitespace character, usually space and tab. \S matches a non-whitespace character.
• \d - matches a digit. Equivalent to [0-9]. \D matches a non-digit.
• \b - matches a word boundary. This sequence in fact has a zero width but it is nevertheless highly useful. \B matches something that is not a word boundary.