%%
%% The LaTeX Companion, 3ed
%%
%% Example 4-2-28 on page I-312 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{xcolor,fvextra}   \fvset{tabcolor=blue}
%StopShownPreambleCommands

\begin{document}
\begin{Verbatim}
123456789012345678901234567890
Two	default	tabs
\end{Verbatim}
\begin{Verbatim}[obeytabs,showtabs]
Three	visible	tab	chars
\end{Verbatim}
\begin{Verbatim}[obeytabs,showtabs,tab=$\bullet$]
Two	new	tabs
\end{Verbatim}
\begin{Verbatim}[obeytabs,tabsize=3,showtabs]
Using	a	special tab	size
\end{Verbatim}
\end{document}