Practical Programming in Tcl & Tk, Third Edition

The regexp Command

The regexp command provides direct access to the regular expression matcher. Not only does it tell you whether a string matches a pattern, it can also extract one or more matching substrings. The return value is 1 if some part of the string matches the pattern; it is 0 otherwise. Its syntax is:

regexp ?flags? pattern string ?match sub1 sub2...?

The flags are described in Table 11-6:

Table 11-6. Options to the regexp command.

-nocase	Lowercase characters in pattern can match either lowercase or uppercase letters in string.
-indices	The match variables each contain a pair of numbers that are in indices delimiting the match within string. Otherwise, the matching string itself is copied into the match variables.
-expanded	The pattern ...