listings package - Can I include a backslash \ in language keyword (\begin) for syntax highlighting in LaTeX code?

Question

I want to highlight a LaTeX code (including backslash \, e.g. \begin). Unfortunately, by default a LaTeX listings package does syntax highlighting only keywords WITHOUT back slash (e.g. begin).

Answer 1

\documentclass{article}
\usepackage[T1]{fontenc}  
\usepackage[scaled=0.82]{beramono}  
\usepackage{listings,xcolor}
\begin{document}

\begin{lstlisting}[basicstyle=\small\ttfamily,language={[LaTeX]TeX},
                   texcsstyle=*\color{red}\bfseries,
                   keywordstyle=\color{blue}\bfseries,
                   morekeywords=alignat,moretexcs=intertext]
\begin{alignat*}{4}
   y &= -4   &+ 3 &+4     &-7      \\
   y &=      &+ 3 &       &-7      \\
   \intertext{Therefore}
   a &= b    &d   &= cccc &e  &= d \\
   a &= bbbb &d   &= c    &e  &= d
\end{alignat*}
\end{lstlisting}

\end{document}