Why does \jobname give *s instead of spaces, and how do I fix this?

Question

When I LaTeX a file names test 1.tex with the code \edef\temp{\jobname.txt}\show\temp, I get

> \temp=macro:
->test*1.txt.

This seems to work fine with LaTeX's internal commands, but if I then mix this with \write18, it fails. For example, something like

\newwrite\tempwrite
\immediate\openout\tempwrite\temp\relax
\immediate\write\tempwrite{test}
\immediate\closeout\tempwrite
\immediate\write18{rm "\temp"}

How can I get a version of \jobname that actually uses spaces instead of stars? (Can I do something fancy with catcodes to make \write18 transform stars into spaces?)

Answer 1

This behaviour is MiKTeX-specific: TeX Live on Windows behaves in the same way as on other platforms, and quotes the file name.

What you can do is convert the * characters into spaces. Something like

\edef\Jobname{\jobname}
\catcode`\*=\active
\def*{ }
\edef\Jobname{"\scantokens\expandafter{\Jobname\noexpand}"}
\catcode`\*=12 %
\show\Jobname

(using e-TeX) will do the task cleanly. Of course, that will only work if there are no * characters in the file name. (There should not be, but it is possible to end up with this type of awkward file name!)