git filter folder

git-filter-folder.sh

#!/bin/bash
set -eux

# Use this script to prune away everything but `foo/bar/somedir`, resulting with only `somedir`
# in the root. Using `--subdirectory-filter` is undesireable because it hoists all the contents
# of `somedir` into the root.

mkdir -p __github-migrate__
mvplz="if [ -d $1 ]; then mv $1 __github-migrate__/; fi;"
git filter-branch -f --tree-filter "$mvplz" HEAD
git filter-branch -f --subdirectory-filter __github-migrate__