%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 3-4-25 on page 165.
%%
%% Copyright (C) 2004 Frank Mittelbach, Michel Goossens,
%%    Johannes Braams, David Carlisle, and Chris Rowley
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%%
%% See http://www.latex-project.org/lppl.txt for details.
%%

\documentclass{ttctexa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{183.0pt}

\addtolength\textwidth{-30pt}

\StartShownPreambleCommands
\usepackage{fancyvrb}
\CustomVerbatimEnvironment{myverbatim}{Verbatim}
        {numbers=left,frame=lines,framerule=2pt}
\StopShownPreambleCommands
\begin{document}
\begin{myverbatim}
The normal case with thick
rules and numbers on the left.
\end{myverbatim}
\begin{myverbatim}[numbers=none,framerule=.6pt]
The exception without numbers
and thinner rules.
\end{myverbatim}
\RecustomVerbatimEnvironment{myverbatim}{Verbatim}
         {numbers=left,frame=none,showspaces=true}
\begin{myverbatim}
And from here on the environment
behaves differently again.
\end{myverbatim}
\end{document}