Locating a pattern within a string

Many times, you may have the need to determine if a specific pattern exists within a string. To accomplish this, Tcl provides the match keyword. Let's look at the syntax and then I will explain the major differences and the real strength of this keyword.

The string syntax is as follows:

string match nocase pattern string

When invoked with the match keyword, the string command will attempt to locate the pattern specified.

The following details the various methods in which the pattern can be passed and illustrates the special characters the pattern can store.

Special Characters	Description
*	Matches any sequence within the string, including null strings.
?	Matches any single character in the string.
[characters]	Matches any character in the set provided. If chars contains a sequential notation of the form a-f, then any characters between a and f (a and f inclusive) will result in a match.
\x	Matches the character specified in x. This avoids...