gitbrute adds a hidden, not-explicitly-supported-by-git field named
'nonce' to the commit at HEAD, and brute forces its value such that
the resulting git commit matches your desired pattern.
Shorter prefixes match more quickly, of course.
Usage:
go run gitbrute.go --pattern ^000000
This amends the last commit of the current repository.
gitbrute is based on a program of the same name written by Brad Fitzpatrick
https://github.com/bradfitz/gitbrute, although its behavior has diverged
significantly.