usage: gitcredit [-h] [-f FILELIST] [-a AUTHORMAP] [-b BLAMEARG] [-o OUTDIR]
                 [-v VERBOSE]
                 [FILE [FILE ...]]

given a list of input paths inside the git repo your current dir is in, give
credit according to `git blame`, optionally creating a fresh git repo without
meaningful history but with a commit per author

positional arguments:
  FILE                  (args X for `git blame X`; added to --filelist file)

optional arguments:
  -h, --help            show this help message and exit
  -f FILELIST, --filelist FILELIST
                        file containing lines X to `git blame X` (from the
                        current dir); - means STDIN - e.g. `find . >
                        /tmp/filelist`
  -a AUTHORMAP, --authormap AUTHORMAP
                        author mapping file - lines of e.g. gitauthorname =
                        Normalized Author <user@example.com> - order is commit
                        order for -o
  -b BLAMEARG, --blamearg BLAMEARG
                        -argument passed to git blame e.g. for copy detection
                        (which can be extremely slow) C CC or CCC
  -o OUTDIR, --outdir OUTDIR
                        outdir (if set) used to store author revision subdirs
                        outdir/0/ outdir/1/ ... with outdir/authors file
  -v VERBOSE, --verbose VERBOSE
                        > 0 means more logging

To create a series of collapsed 1-per-author git commits in a fresh repository by parsing -o OUTDIR:

find_srcs() {
    find "$@" -name '*.java' -o -name '*.py' -o -name '*.md' \
      -o -name '*.pl' -o -name '*.sh' -o -name '*.bat' \
      -o -name '*.[chi]pp' -o -name '*.[ch]' -o -name '*.cc' -o -name '*.hh' \
      -o -name '.gitignore'
}
gitsubset() {
    fullrepo=`pwd`
    subset=$fullrepo/../subset
    mkdir $subset
    find_srcs $fullrepo > $subset/srcs
    gitcredit -o $subset -f $subset/srcs
    cd $subset
    mkdir repo
    cd repo
    git init
    while read -d ' ' commit; do
        read author
        cp -r ../$commit/. .
        git add -A .
        git commit -m "$author import" --author="$author"
    done < ../authors
    git tag initial HEAD
    git log
    git archive --format=tar.gz -o ../initial.tar.gz -v HEAD
}

cd my-git-repo && gitsubset

TODO: move the above shell commands into a python option -r REPODIR