[OS X TeX] BackExercise.tex

[Alain Schremmer]

I found this file as I was cleaning my HD---or trying to.

Here is how it starts:

> \documentclass{book}
> \usepackage{amsmath}
> \usepackage{comment}
> %\chapterstyle{bianchi}
>
> \newoutputstream{backansout}
> \newoutputstream{solutionsout}
>
> \newenvironment{Exercises}
> {\openoutputfile{\jobname.backans}{backansout}
> \openoutputfile{\jobname.solns}{solutionsout}}
> {\closeoutputstream{backansout}
> \closeoutputstream{solutionsout}}
>
> \newcounter{exercise}[section]
> \renewcommand{\theexercise}{\arabic{exercise}}
>
> \newenvironment{exercise}%
> {\refstepcounter{exercise}
> \par\noindent\textbf{\theexercise}.}
> {\par}



It won't compile claiming

Excluding comment 'comment')
./BackExercise.tex:7: Undefined control sequence.
l.7 \newoutputstream
                     {backansout}
?

Does anyone have an idea where it could have come from? (Google, of  
course, thinks it is about back pain.)

Curious regards
--schremmer