Call LaTeX on a named pipe (fifo)?

Question

I'm running LaTeX on a named pipe fifo on Unix. I create the fifo like-so:

$ mkfifo fifo

I then run LaTeX like-so:

$ latex fifo

This process blocks and has no output until I write to the fifo from another shell:

$ echo "\\end" > fifo

Then the $ latex fifo output becomes:

This is pdfTeXk, Version 3.1415926-1.40.9 (Web2C 7.5.7)
%&-line parsing enabled.
entering extended mode

However, the LaTeX process never ends. How can you get LaTeX to end? I've tried sending it chr(0) and chr(4) (i.e. ctrl-d), but neither works. Is there some command that will tell LaTeX to exit (i.e. something like \exit)?

Thanks for reading.

EDIT:

It is noteworthy that when you run tex instead of a variant of latex then the following works as expected:

$ echo "story\\end" > fifo

(meanwhile, in the tex console)

$ tex fifo
This is TeX, Version 3.1415926 (Web2C 7.5.7)
(./fifo [1] )
Output written on fifo.dvi (1 page, 212 bytes).
Transcript written on fifo.log.

However, although Leslie Lamport notes in A Document Preparation System LaTeX on page 233 that \end has been replaced by \end{document}, neither of the following ends a LaTeX session:

$ echo "\begin{document}story\end{document}"
$ echo "\\begin{document}story\\end{document}"

brianegge brianegge · Accepted Answer · 2009-09-18T04:28:44

I would suggest allow your shell to direct the fifo pipe to the standard in.

latex < fifo

When I do that, I get this output first:

This is pdfeTeXk, Version 3.141592-1.21a-2.2 (Web2C 7.5.4) (format=latex 2009.3.25)  18 SEP 2009 14:25
entering extended mode
 file:line:error style messages enabled.
 %&-line parsing enabled.

and then after the echo command:

**\end

*
! Emergency stop.
<*> \end

End of file on the terminal!

Call LaTeX on a named pipe (fifo)?

2 Answers