This approach will not work across page boundaries (which is why I upvoted Werner's answer). But since I did it, I'll present it. I set up \lrlineno[start no]{text}
.
Basically, I print it out in white, with left line numbers, then do a \vspace
to the beginning of the block, and reprint it out in black, using right line numbers.
\documentclass{article}
\usepackage[left]{lineno}
\usepackage{xcolor}
\usepackage{blindtext}
\newlength\tmplen
\newcommand\lrlineno[2][1]{%
\linenumbers%
\setcounter{linenumber}{#1}%
\leftlinenumbers%
\color{white}#2\color{black}%
\par%
\setcounter{linenumber}{#1}%
\setbox0=\vbox{#2}%
\setlength\tmplen{\dimexpr\dp0+\ht0+\the\dp\strutbox}%
\vspace*{-\tmplen}%
\rightlinenumbers%
#2%
\par%
\nolinenumbers%
}
\begin{document}
Testing left-right line numbers, beginning at 3
\lrlineno[3]{\blindtext}
Test is complete.
\end{document}
