Emulating a shell environment

Question

I'm trying to define a new environment, which emulates a shell. The way I would like to use it:

\begin{shell}
\item{echo foo}{foo}
\item{echo bar}{bar}
\end{shell}

Which should produce:

This is my shell prompt
1> echo foo
foo
2> echo bar
bar

What I have so far:

\newcommand{shellprompt}{This is my shell prompt}
\newenvironment{shell}{
  \shellprompt
  \begin{enumerate}[\hspace{15px} 1\textgreater]
    \let\olditem\item
    \renewcommand\item{\olditem}
  }{
  \end{enumerate}
}

How do I redefine the \item command so it accepts a second parameter and prints it on a second line?

Bonus: How do I wrap everything (prompt + items) in a verbatim environment?

Answer 1

This is a possibility:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{fancyvrb}
\DefineVerbatimEnvironment{shell}{Verbatim}{commandchars=\%\{\},formatcom=\setcounter{prompt}{0}}
\newcounter{prompt}
\newcommand{\prompt}{\stepcounter{prompt}\theprompt>}

\begin{document}
\begin{shell}
%prompt echo foo
foo
%prompt echo bar
bar
\end{shell}
\end{document}

In the shell command you'll need to escape %, { and } with a %, so, to print

% { }

you have to input

%% %{ %}

If you want to add the same first line to all environments,

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{fancyvrb}
\DefineVerbatimEnvironment{shell}{Verbatim}{commandchars=\%\{\},formatcom=\setcounter{prompt}{0}\start}
\newcounter{prompt}
\newcommand{\prompt}{\stepcounter{prompt}\theprompt>}
\newcommand{\start}{\noindent This is my shell prompt\par}

\begin{document}
\begin{shell}
%prompt echo foo{}
foo
%prompt echo bar
bar
\end{shell}
\end{document}

Just redefine \start to suit.