Getting fancyvrb and mdframed to work togegher

Question

I would like to format terminal output as follows:

• white text on black background
• commands written by the user are emphasized (slanted typewriter)

Using a combination of mdframed and fancyvrb I got this to work quite nicely:

\DefineVerbatimEnvironment{termverb}{Verbatim}{commandchars=\\\{\}}
\newcommand{\shellcommand}[1]{\textbf{\$} {\fontfamily{cmtt}\fontshape{sl}\selectfont{#1}}}

\begin{document}

This is regular text.

\begin{mdframed}[backgroundcolor=black,fontcolor=white]
\begin{termverb}
\shellcommand{./do_something.py}
This is printed text that works properly.
\end{termverb}
\end{mdframed}

Now I'd like to create a custom environment for this. However I can't get that to work. No matter which combination of commands, environments and verbatim alternates I use, it will always lead to a parse error. Removing mdframed or verbatim works, but both of them at the same time do not. This is the closest I got, it produces the correct output but requires pressing enter about 10 times when running pdflatex to ignore the errors:

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{fancyvrb}
\usepackage{mdframed}
\pagestyle{empty}

\DefineVerbatimEnvironment{termverb}{Verbatim}{commandchars=\\\{\}}
\newenvironment{terminal}
               {\begin{mdframed}[backgroundcolor=black,fontcolor=white]
               \begin{termverb}}
               {\end{termverb}
               \end{mdframed}}
\newcommand{\shellcommand}[1]{\textbf{\$} {\fontfamily{cmtt}\fontshape{sl}\selectfont{#1}}}

\begin{document}

This is regular text.

\begin{mdframed}[backgroundcolor=black,fontcolor=white]
\begin{termverb}
\shellcommand{./do_something.py}
This is printed text that works properly.
\end{termverb}
\end{mdframed}

Regular text in the middle.

\begin{terminal}
\shellcommand{./do_something.py}
This does not work!
\end{terminal}

Regular text at the end.

\end{document}

Any help would be appreciated. Thanks.

Edit: It turns out this is not really possible with fancyvrb. The working solution was to change to alltt for the verbatim input part. Plain verbatim does not work because I need to get macro expansion inside the verb environment.

Answer 1

Use the short syntax \command ... \endcommand for the definition.

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{fancyvrb}
\usepackage{mdframed}
\pagestyle{empty}

\DefineVerbatimEnvironment{termverb}{Verbatim}{commandchars=\\\{\}}
\newenvironment{terminal}
  {\mdframed[backgroundcolor=black,fontcolor=white] \termverb}
  {\endtermverb\endmdframed}
\newcommand\shellcommand[1]{\textbf{\$} {\fontfamily{cmtt}\fontshape{sl}\selectfont{#1}}}

\begin{document}

    This is regular text.

\begin{mdframed}[backgroundcolor=black,fontcolor=white]
\begin{termverb}
\shellcommand{./do_something.py}
This is printed text that works properly.
\end{termverb}
\end{mdframed}

Regular text in the middle.

\begin{terminal}
\shellcommand{./do_something.py}
This does not work!
\end{terminal}

Regular text at the end.

\end{document}

Answer 2

mdframed has a macro called \surroundwithmdframed. Use this macro on your environment defined with \DefineVerbatimEnvironment. Code:

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{fancyvrb}
\usepackage{mdframed}
\pagestyle{empty}

\DefineVerbatimEnvironment{terminal}{Verbatim}{commandchars=\\\{\}}

\surroundwithmdframed[%
backgroundcolor=black,
fontcolor=white
]{terminal}

\newcommand{\shellcommand}[1]{%
  \textbf{\$} {\fontfamily{cmtt}\fontshape{sl}\selectfont #1}%
}

\begin{document}

This is regular text.

\begin{terminal}
\shellcommand{./do_something.py}
This is printed text that works properly.
\end{terminal}

Regular text in the middle.

\begin{terminal}
\shellcommand{./do_something.py}
This does not work!
\end{terminal}

Regular text at the end.

\end{document}