• .blof - binary linear object file

• .blch - binary linear object file with checksum header

.blof files are just ascii binary representation (0 and 1 characters) of whatever files or folders you decide to archive or whatever contents that you pass in on stdin to the blof utility when calling it with no arguments, but first being added into a .tar archive and then the .tar being compressed with the gzip -9 command. The binary characters (again, just ascii 0 and 1) are all contiguous with no spaces anywhere and there's no newline at the end of the string of characters. .blof files are the foundation for .blch files, which in turn are the better, more complete format to be preferred to be used in most cases.

.blch is the archive file type that's better to use than .blof files, for most purposes. .blch files (pronounced "BLCH", "BUL-CH", or "belch" if you prefer (eww!)) are just .blof files with a header at the beginning and then a single whitespace character, followed by the contents of a .blof file. The header is the output of the command sha256sum -z --tag being used on the ascii 0 and 1 characters which appear after the header in the .blch file, but with some post-processing to remove all the whitespace from the output of that sha checksum command and to remove the null byte it would otherwise introduce into the output string.

That's the format for .blch and their foundational .blof file types. This git repository is the reference implementation of the official tooling for creating and working with blof and blch files, and it currently offers a bash implementation using standard tools available on most or all Linux and other similar kinds of operating systems.

Please file an issue if you find any bugs, and submit pull requests if you want, and I'll address them time-permitting.

These are very minimal and lightweight file format specifications, and I hope you find them as useful as I do. I had a bit of help from Tim, my custom GPT-4o-based ChatGPT model on this project, but mostly just a consult, and I did most of it by hand like in the old days. :)

Enjoy!

~defcron