... Christiansen, and Jon Orwant (O'Reilly) Mastering Regular Expressions, by Jeffrey E.F Friedl (O'Reilly), is another excellent source of information on regular expressions 10.1.1 Literal Characters As we've ... subsequent characters are never even considered 10.1.4 Alternation, Grouping, and References The regular expression grammar includes special characters for specifying alternatives, grouping subexpressions, ... and referencing operators Table 10-4 Regular expression alternation, grouping, and reference characters Character Meaning | Alternation Match either the subexpressions to the left or the subexpression...