Customizing pdfLaTeX for a particular file with AUCTeX?

Question

I'm trying to use the TikZ 'external' library, available as of PGF 2.10. This requires running pdfLaTeX with the option -shell-escape. I usually run pdfLaTeX from AUCTeX with the option

(TeX-PDF-mode t)

So C-c C-c runs pdfLaTeX. Can I add a line to my LaTeX file so that AUCTeX will know to run pdfLaTeX with the -shell-escape option for this file only, seeing as this is apparently a security issue, and only partially enabled by default? I don't know if this is possible, but similar things are possible. See for example the tex.sx question Force different TeX engine for specific files. If possible this would presumably use file variables.

If not, I know it is possible to customize it globally for all files in .emacs. Currently, I'm not sure how to do that either. Preferably via M-x customize, but I find those menus quite confusing

See for example http://thread.gmane.org/gmane.emacs.auctex.general/538 where David Kastrup seems to suggest that the per file approach is possible. Ie.

"Anyway, you could use the file variable section to change the command just in those files where you want it."

Also see http://thread.gmane.org/gmane.emacs.auctex.general/710

UPDATE: Based on input from the auctex mailing list, the answers suggested by people here should work. It is not clear why it doesn't, but the problem may be specific to the Debian package. Marcus Frings pointed me to his bug report in the thread above. The bottom line is there appears to be a problem with the Debian package, which is not present in vanilla auctex, and nobody knows why. The maintainer, who one would expect to look into this, shows no interest in doing so, unfortunately.

Answer 1

Please be aware that limited FS access is allowed without shell-escape in TL10, using \write18. Miktex probably has something similar.

I add the following to files, which are always to be shell-escaped.

%%% LaTeX-command: "latex -shell-escape"

I also have the following snippet in my .emacs for adding shell escape on the go:

;; toggle shell escape using C-c C-t C-x
(defun TeX-toggle-escape nil (interactive)
  "Toggle Shell Escape"
  (setq LaTeX-command
    (if (string= LaTeX-command "latex") "latex -shell-escape" "latex")))
(add-hook 'LaTeX-mode-hook
      (lambda nil
        (local-set-key (kbd "C-c C-t x") 'TeX-toggle-escape)))

Edit: here's a nicer function which tells you what is going on:

;; toggel shell escape using C-c C-t C-x
(defun TeX-toggle-escape nil (interactive)
"Toggle Shell Escape"
(setq LaTeX-command
  (if (string= LaTeX-command "latex") "latex -shell-escape"
    "latex"))
(message (concat "shell escape "
         (if (string= LaTeX-command "latex -shell-escape")
         "enabled"
           "disabled"))
     ))
(add-hook 'LaTeX-mode-hook
      (lambda nil
    (local-set-key (kbd "C-c C-t x") 'TeX-toggle-escape)))

Answer 2

The global customization is done by entering

M-x customize-variable RET LaTeX-command RET

(as David Kastrup described in http://thread.gmane.org/gmane.emacs.auctex.general/538) and changing the LaTeX-command variable. He didn't say what the variable should be changed to, but the answer is from the default, which is

latex

to

latex -shell-escape

If this is set and saved, it appears in .emacs as

(LaTeX-command "latex -shell-escape")

in the custom-set-variables list.

I still don't know how to do this on a per file basis.

UPDATE: The preceding approach of setting latex-command doesn't work with xelatex for me, but the approach in this answer to "Using minted (source code LaTeX package) with emacs/auctex" does, namely adding

(eval-after-load "tex" 
  '(setcdr (assoc "LaTeX" TeX-command-list)
          '("%`%l%(mode) -shell-escape%' %t"
          TeX-run-TeX nil (latex-mode doctex-mode) :help "Run LaTeX")
    )
  )

to your .emacs file.

Of course, setting this per file using local variables would be preferable to either method, because enabling -shell-escape globally is unnecessary.

Answer 3

Solution 1: use local variables. Insert the following at the end of a LaTeX file you want to allow to use shell escapes:

%%% Local Variables:
%%% LaTeX-command: "latex -shell-escape"
%%% End:

Note that this is only applied once the file is closed and re-opened in emacs. (you need the "Local Variables:" and "End:" line).

Solution 2: use LaTeX-command-style to automagically turn on shell escapes for every file in which you use the pgf package (a little more dangerous?). Put the following in your .emacs:

(setq LaTeX-command-style
  '(("^pgf$" "%(PDF)%(latex) -shell-escape %S%(PDFout)")
    ("" "%(PDF)%(latex) %S%(PDFout)")))

You may also use the emacs customization system to set this up.

Answer 4

Solution 1 of Hendrik Vogt does not work for me any longer (emacs 23.3.1, AUCTeX-version 11.86). Instead I use the synctex-flags:

%%% Local Variables:
%%% TeX-source-correlate-mode: t
%%% TeX-synctex-tex-flags: "-synctex=1 -shell-escape"
%%% End: