%%
%% The LaTeX Companion, 3ed
%%
%% Example 4-2-29 on page I-313 in "Customization keys for typesetting".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{159.0pt}

%StartShownPreambleCommands
\usepackage{fancyvrb}
%StopShownPreambleCommands

\begin{document}
\begin{Verbatim}[commandchars=\|\[\],commentchar=\!]
We can |emph[emphasize] text
! see above (this line is invisible)
Line with label|label[linea] ! removes new line
is shown here.
Careful: last line lost ! because of comment
\end{Verbatim}
On line~\ref{linea} we see\ldots
\end{document}