Underscore in listing color

Question

How to make this code works:

\documentclass[dvipsnames]{report}
\usepackage[utf8]{inputenc}
\usepackage{xspace}
\usepackage{xcolor}
\usepackage{listings}

\lstdefinestyle{s}{escapechar={|}}

\begin{document}

\begin{lstlisting}[style=s]
foo
|\color{red}{bar_42}|
\end{lstlisting}

\end{document}

Without having to add a \ before the _ ?

I have a large portion of code to put into my listing with lots of _ and I don't want to manually add a \ everywhere.

Answer 1

You can load the package underscore. With that package, the character _ is available in text mode of LaTeX.

\documentclass{report}
\usepackage{xspace}
\usepackage{xcolor}
\usepackage{listings}
\usepackage{underscore}

\lstdefinestyle{s}{escapechar={|}}

\begin{document}

\begin{lstlisting}[style=s]
foo
|\color{red}{bar_42}|
\end{lstlisting}

\end{document}