This is a front end to the gnu.regexp.util.Grep class which sets the
syntax used to RE_SYNTAX_EGREP, which aims to emulate the standard UNIX
egrep command.
Returns the index within the input string used to generate this match
where subexpression number sub begins, or -1 if
the subexpression does not exist.
Invokes the grep() function below with the command line arguments
and using the RESyntax.RE_SYNTAX_GREP syntax, which attempts to
emulate the traditional UNIX grep syntax.
Defines a constant (0xFFFF was somewhat arbitrarily chosen)
that can be returned by the charAt() function indicating that
the specified index is out of range.
Substitutes the replacement text for the first match found in the input
string, beginning at the specified index position and using the
specified execution flags.
Substitutes the replacement text for each non-overlapping match found
in the input text, starting at the specified index and using the
specified execution flags.