Integrate handcrafted binary and documentation
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There are times when a binary file has to be crafted by hand, be it for testing purposes, for research, or just for some weird kind of fun. Usually, a hex editor is the tool of choice for straightforward binary editing. But what about documentation? There is no way to enter inline comments or other explanatory prose in a hex editor, leading to separation of hex code and documentation. (Or worse, to no documentation at all.)

Wouldn't it be great if there was a way to combine binary (expressed as hex code) and textual content in the same file? If both a binary file and accompanying documentation in formats like HTML or PDF could be generated from the same source file? There is!

Just write a Markdown file like this example. Run it through your favourite Markdown converter (mine is Pandoc) to create a pretty HTML or PDF document; run it through lb to create a binary file from its hex content.

                pandoc -> documentation.{html,pdf,docx,...}
                lb     -> binary.bmp

Obviously, this is inspired by Donald Knuth's ideas on literate programming.


  • The lb (literate binary) tool expects a Markdown file as input.
  • All code blocks in this file tied together form the content of the binary file created by lb. All other content including inline code in backticks `like this` is ignored, only code blocks are relevant.
  • The code blocks must contain nothing but hex characters (upper or lower case), macros, whitespace and comments.
  • Macros are used to write long, repetitive hex patterns in a compact way. They consist of a sequence of hex characters and a quantifier, similar to regular expression syntax. For example, the macro (ff00){3} expands to ff00ff00ff00. Macros may be nested, like (ff(00e2){2}00((21){4}03){12}){8}.
  • Comments start with a # sign and end at the end of the line.
  • There is one exception to the "all code blocks" rule; fenced code blocks with the .nobin class are ignored as well. This can be used to add code other than binary, or to "comment out" a whole code block.

Here is a complete example describing a simple Bitmap image file; there are several others in the examples/ directory.


Get a binary here and put it in your PATH. Then:

$ lb --help
$ lb --output binary.bmp


Pull requests for well-documented example files (minimal file format examples, misuse of format specifications, ...) are greatly appreciated!

Building from source

This tool is written in Haskell. It is recommended to use Stack for building. Install Stack, clone the Git repository, change to its top level directory and run the following commands:

$ stack setup
$ stack build
$ stack install

This will install the lb executable to ~/.local/bin/ on Linux and to %AppData%\local\bin on Windows.