[tex-live] [XeTeX] Problem with XeTeX's (and perhaps other binaries -- not investigated) handling of --output-directory

[mskala at ansuz.sooke.bc.ca]

On Sun, 15 Jan 2017, David Carlisle wrote:
>                Specify the directory dirname to which output files are
> written. Also look for
>                input files in dirname first, before looking along the normal
> search path. See
>                Section 3.4 [Output file location], page 9.

The general principle here is that TeX expects to modify files in place.
Stuff like the multi-stage compilation of LaTeX implicitly assumes that it
works this way, but it is TeX, not LaTeX, that originally instituted the
concept.  It's not in keeping with the Unix philosophy of programs working
as pipes, and it causes trouble for people with other expectations.  For
instance, I nearly always run TeX engines through Makefiles, and the
rewriting of files that are used as both input and output screws up how
Make works and requires complicated side handling.  But the "modify in
place" philosophy is built into TeX at a very deep level; it's not going
to change soon; and it's probably pointless to expect that it could be
turned off in a real way by a simple command line option.

-- 
Matthew Skala
mskala at ansuz.sooke.bc.ca                 People before principles.
http://ansuz.sooke.bc.ca/