Well, I don't see any good reason to write this in C. The operations performed are very basic, and it only obscures what you're doing. Further, your program relies on Ruby and Grit (that gem itself an onerous dependency) to do things that require neither tool. This seems to be the sort of thing that should either be in pure C if you really want that, or as a standalone script that requires nothing, given its simplicity. And if it were a standalone Python script, for instance, you could easily use the "inspect" module to write some inline source to file. All that Ruby source in a C header is a very odd decision to me.

If I were writing this with the understanding that it were not to work on Windows (which you seem to have decided, upon reading the source), I think I'd just use a simple shell script.

I will add that there is no good reason at all to require an "init" command, as that could be a simple get-or-set method when another command is used.

Viewing the commit history, you need to be far more careful with how you use git and how you define your .gitignore.