\section{REGEXPREP Regular Expression Replacement Function}

\subsection{Usage}

Replaces regular expressions in the provided string.  The syntax for its
use is 
\begin{verbatim}
  outstring = regexprep(instring,pattern,replacement,modes)
\end{verbatim}
Here \verb|instring| is the string to be operated on.  And \verb|pattern| is a regular
expression of the type accepted by \verb|regexp|.  For each match, the contents
of the matched string are replaced with the replacement text.  Tokens in the
regular expression can be used in the replacement text using \verb|$N| where \verb|N|
is the number of the token to use.  You can also specify the same \verb|mode| 
flags that are used by \verb|regexp|.
