Returns a valid regular expression which will match string, ignoring case. This expression is string with each character converted to a bracket expression; this bracket expression contains that character's uppercase and lowercase form if applicable, otherwise it contains the original character twice.
[Ff][Oo][Oo][ ][Bb][Aa][Rr] |
This can be used to achieve case insensitive pattern matching in products which support only case sensitive regular expressions.