shellout.sty

\makeatletter
%\usepackage{newverbs}

\newwrite\shellout@out
\def\shellout@writeout@start#1{%
  \begingroup
  \immediate\openout\shellout@out#1%
  \let\do\@makeother\dospecials%
  \catcode`\^^M\active%
  \def\verbatim@processline{%
    \immediate\write\shellout@out{\the\verbatim@line}}%
}%

\def\shellout@writeout@end{%
  \immediate\closeout\shellout@out\endgroup%
}%

\newcounter{shellout@shell@id}
\counterwithin{shellout@shell@id}{subsubsection}

\def\shellout@setup#1{%
  \stepcounter{shellout@shell@id}%
  \gdef\shellout@shell@cmd{#1}%
  \gdef\shellout@shell@infile{\theshelloutcacheprefix.\theshellout@shell@id.shellin.tmp}%
  \gdef\shellout@shell@outfile{\theshelloutcacheprefix.\theshellout@shell@id.shellout.tex}%
}

\def\shellout@shell@start#1{%
  \shellout@setup{#1}%
  \shellout@writeout@start{\shellout@shell@infile}%
}%

\def\shellout@shell@perform{%
  \ifx\shellout@cachemode 0%
    \immediate\write18{\theshelloutbin'' \shellout@shell@infile'' \shellout@shell@outfile'' \shellout@shell@cmd''}%
  \fi%
  \immediate\input{\shellout@shell@outfile}%
}

\def\shellout@shell@end{%
\shellout@writeout@end%
\noindent\obeyspaces\shellout@shell@perform%
}

\def\shelloutone#1{%
  \stepcounter{shellout@shell@id}%
  \gdef\shellout@shell@cmd{#1}%
  \gdef\shellout@shell@infile{/dev/null}%
  \gdef\shellout@shell@outfile{\theshelloutcacheprefix.\theshellout@shell@id.shellout.tex}%
  \shellout@shell@perform%
}

\def\shelloutcacheprefix#1{
  \gdef\theshelloutcacheprefix{#1}
}

\gdef\theshelloutbin{shellout}
\def\shelloutbin#1{
  \gdef\theshelloutbin{#1}
}

\shelloutcacheprefix{\jobname}

\def\shelloutcachemode{\let\shellout@cachemode1}%
\def\shelloutnocachemode{\let\shellout@cachemode0}%
\shelloutnocachemode%

\newenvironment{shellout}[1]{
  \begingroup
  \@bsphack%
  \shellout@shell@start{#1}%
  \verbatim
}{
  \endverbatim%
  \@esphack

  \shellout@shell@end%
  \endgroup
}

\makeatother