As in LaTeX -- line-breaks are obeyed and everything is in typewriter font. See also: the `flushverbatim' and `display' environments.

You can't nest other environments inside verbatim environments. A trick (hack) you can use to put a verbatim environment inside another is to indent the inner one by one space, as in:

\begin{verbatim}

...

\begin{verbatim}

...

\end{verbatim}

...

\end{verbatim}