# runtexshebang: Lua script running LaTeX document files with TeX-style shebang Lua script running LaTeX document files with a TeX-style shebang (`%#!`) ## What is a TeX-style shebang (`%#!`) In short, a TeX-style shebang (`%#!`) is a special kind of TeX comment that you include in your TeX/LaTeX document file to tell the operating system's shell how to run the file for the rest of the file: ``` latex %#!lualatex foo.tex \documentclass{article} \begin{document} Hello, {\LaTeX} World! Happy {\TeX}ing. \end{document} ``` If you are using a TeX-style shebang, it must appear on the line that matched 20 lines or less in your LaTeX document, and it has to start with a TeX comment symbol (`%`) followed by a hash sign (`#`) and an exclamation mark (`!`), colloquially known as the bang, hence the name shebang for TeX/LaTeX. ## Getting started ### 1. Install `runtexshebang.lua` in your TeX Live system. The `runtexshebang` package is contained in TeX Live 2023 or higher. So, it can be installed through ``` shell $ sudo tlmgr install runtexshebang ``` If you manually install `runtexshebang.lua` in your TeX Live system, you can install it through ``` shell cp runtexshebang.lua /some/where/TEXMFDIST_or_TEXMFLOCAL/scripts/runtexshebang/runtexshebang.lua cd TEXLIVE_BIN_DIRECTORY ln -s ../../TEXMFDIST_or_TEXMFLOCAL/scripts/runtexshebang/runtexshebang.lua runtexshebang ``` ### 2. Make a sample file with a TeX-style shebang. Make the following LaTeX document. ``` latex %#!lualatex foo.tex \documentclass{article} \begin{document} Hello, {\LaTeX} World! Happy {\TeX}ing. \end{document} ``` ### 3. Run the sample file. ``` shell runtexshebang foo.tex ``` Then, it will run `lualatex foo.tex`. To see which command would be run without running it, use `runtexshebang --dry-run foo.tex`. ## Examples ### TeXworks #### Settings 1. Open "Typesetting" tab in TeXworks Preferences. 2. Add the tool configuration "runtexshebang" in "Processing tools" as below. - Name: `runtexshebang` - Program: `runtexshebang` - Arguments: `$fullname` - Check "View PDF after running" (if necessary) #### LaTeX document in the internal editor of TeXwork `% !TEX program = ` is a magic comment of TeXworks. You can set one processing tool as `% !TEX program = `. ``` latex % !TEX program = runtexshebang %#! lualatex --synctex=1 foo ``` ### LaTeX Workshop: Visual Studio Code #### Settings Nothing! #### LaTeX document in Visual Studio Code `% !TEX program = ` is a magic comment of LaTeX Workshop. You need another magic comment to the target LaTeX document file as below. ``` latex % !TEX program = runtexshebang % !TEX options = "%DOC%".tex %#! lualatex --synctex=1 foo ``` ### TeXShop #### Settings There the “Engine” settings for the command lines "TeX+dvipdfmx / TeX+dvips+distiller" as follows. * TeX: `runtexshebang` * LaTeX: `runtexshebang` #### LaTeX document in the internal editor of TeXShop `% !TEX program = ` is a magic comment of TeXShop. ``` latex % !TEX program = runtexshebang %#! lualatex --synctex=1 foo ``` ## Applications ### What does the PATH variable set in my editor? ``` latex %#! echo $PATH ``` ### How about general configuration information for the activated TeX Live version and its configuration in my editor? ``` latex %#! tlmgr conf ``` ### Otherwise You can run any command line on your OSs. For example, you can use any build tools as follows: `make`, `rake`, `llmk`, `latexmk`, and so on. ``` latex %#! make foo.pdf % #! rake foo.pdf % #! llmk % #! latexmk foo %% and so on. ``` You can typeset a LaTeX document file in a Docker container as below. ``` latex %#! docker run -i --rm --workdir /data --mount type=bind,src=$(pwd)/,dst=/data/ bar/foo lualatex foo ``` ## Security * **runtexshebang executes the `%#!` line of your document as a shell command line** (`/bin/sh -c` on Unix, `cmd.exe /c` on Windows). Running `runtexshebang foo.tex` is equivalent to typing the contents of its `%#!` line into your terminal yourself. Treat `.tex` files with a `%#!` line exactly like a `Makefile` or a `latexmkrc`: read the first lines before running them, and only use runtexshebang on documents you trust. * **Editor integration widens the exposure.** Once you have registered runtexshebang as a typesetting tool or engine, every document that carries `% !TEX program = runtexshebang` and a `%#!` line will execute that line when you press "Typeset". Review the `%#!` line of documents you received from others. runtexshebang prints `runtexshebang: running: ` on stderr (the editor console) before executing it, and `runtexshebang --dry-run foo.tex` prints the line without executing it. * **runtexshebang must never be added to `shell_escape_commands` in `texmf.cnf`** (or to any other restricted-shell-escape allow list). If it were, any document compiled with the default restricted shell escape could run arbitrary commands via `\write18{runtexshebang evil.tex}`. It is intentionally absent from that list and is not designed to be called from `\write18`. It is a build tool that the user invokes, like `make`, `latexmk`, `arara` or `llmk`. * runtexshebang loads no Lua code (no `require`, no `dofile`) and reads no configuration file. Its behaviour depends only on its command-line arguments, the first 20 lines of the given file, and the environment (`PATH`, `COMSPEC`). * The command is located through your `PATH`. On Windows, `cmd.exe` normally looks in the current directory first, so an executable placed next to the document could shadow a TeX Live program named on the shebang line. runtexshebang sets `NoDefaultCurrentDirectoryInExePath=1` before running the command to switch that lookup off. * Tampering with `runtexshebang.lua` itself requires write access to the TeX Live tree, the same as for any other program shipped with TeX Live; that is covered by `tlmgr`'s signature verification, not by this script. * The exit status of the executed command is passed through, so editors and `make` can detect failures. runtexshebang itself exits 1 on usage or file errors and 2 when no `%#!` line is found in the first 20 lines. * Only lines that start with `%#!` in column 1 are recognised; `% #!` and ` %#!` are ignored on purpose, which lets you keep alternative command lines in the file as plain comments. A UTF-8 byte order mark before `%#!` on the first line is ignored, and CRLF line endings are handled on every platform. ## References ### Commentary * [TeXworks、TeXShop、VSCodeでTeX-style shebangしてみた - Qiita](https://qiita.com/munepi/items/a30c68133cfffbf4d189) (in Japanese) ### Tools supporting `%#!` * [YaTeX](https://www.yatex.org/): Yet Another TeX mode for Emacs * [llmk](https://github.com/wtsnjp/llmk): Light LaTeX Make Enjoy Happy TeXing! ## License This program is licensed under the conditions of the LaTeX Project Public License, either version 1.3c of this license or any later version. -------------------- Munehiro Yamamoto https://github.com/munepi