Number every line of pages

Question

When editing documents it is convenient to have all the lines on a page numbered (on the left margin) so that the reviewer can refer to them in his report. How can I achieve this with LaTeX?

Answer 1

As Martin Scharrer has pointed out -- and to answer the general question once and for all --: Use the lineno package. (The package allows to number every line, as shown in its documentation.) See this entry of the UK TeX FAQ for possible pitfalls and alternatives.

Answer 2

A slightly different approach to that of the faq pointed out by Lockstep.

Firsty, we need to build a box 3em wide to hold the numbers of all the lines. This box will be later positioned at the left margin and unboxed.

 \newsavebox{\@linebox}
 \savebox{\@linebox}[3em][t]{\parbox[t]{3em}{%
   \@tempcnta\@ne\relax
   \loop{\underline{\scriptsize\the\@tempcnta}}\\
     \advance\@tempcnta by \@ne\ifnum\@tempcnta<48\repeat}}

We use Knuth's loop to generate the line numbers. We can position the box and typeset the line numbers by using thr \put command from the LaTeX's picture environment (although TikZ afficionados can use TikZ). As we need this box on every page, we use the fancyhdr package to achieve this, rather than messing with the output routines. Other possibilities is the background package etc.

\fancyhead[LO]{%
\begin{picture}(0,0)%
  \put(-18,-25){\usebox{\@linebox}}%
 \end{picture}}

You should place the whole code within a conditional to switch between draft and final mode, depending on your class. The full minimal is shown below.

\documentclass[10pt]{article}
\usepackage{fancyhdr,lipsum}
\makeatletter

 \newsavebox{\@linebox}
 \savebox{\@linebox}[3em][t]{\parbox[t]{3em}{%
   \@tempcnta\@ne\relax
   \loop{\underline{\scriptsize\the\@tempcnta}}\\
     \advance\@tempcnta by \@ne\ifnum\@tempcnta<48\repeat}}

 \pagestyle{fancy}
 \fancyhead{}
 \fancyfoot{}
 \fancyhead[CO]{\scriptsize How to Count Lines}
 \fancyhead[RO,LE]{\footnotesize\thepage}
%% insert this block within a conditional
 \fancyhead[LE]{\footnotesize\thepage\begin{picture}(0,0)%
      \put(-26,-25){\usebox{\@linebox}}%
      \end{picture}}

 \fancyhead[LO]{%
    \begin{picture}(0,0)%
      \put(-18,-25){\usebox{\@linebox}}%
     \end{picture}}
\fancyfoot[C]{\scriptsize Draft copy}
%% end conditional
\makeatother
\begin{document}
\section*{Lorem Ipsum}
\lipsum
\end{document}