%%
%% The LaTeX Companion, 3ed
%%
%% Example 4-3-4 on page I-336 in "lineno --- Numbering lines of text".
%%
%% 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{207.0pt}

  \addtolength\textwidth{-30pt}
  \addtolength\parindent{-6pt}      % fudge the example a bit for the box size

%StartShownPreambleCommands
\usepackage{amsmath}
\usepackage[mathlines]{lineno}
\linenumbers

%StopShownPreambleCommands

\begin{document}
All math displays now show line numbers
  \[ x \neq y \]
and the paragraph texts like this one
 \begin{align} x \neq y \end{align}
correctly show line numbers as well.
\end{document}