github-split.sh

gistfile1.sh

#!/bin/sh
# Usage: github-split org/project directory new-project

REPO=$1
FOLDER=$2
NEW_REPO=$3

function usage() {
    echo ""
    echo "Usage: $0 <repo> <folder> <new_repo>"
    echo "\trepo - The source repo to pull from, e.g. org/project-name"
    echo "\tfolder - The folder to split"
    echo "\tnew_repo - The new repo name, e.g. new-project-name"
    exit 1
}

[ $# -le 2 ] && usage

echo "Getting the repo and putting it in /tmp"
git clone git@github.com:$REPO /tmp/$NEW_REPO
cd /tmp/$NEW_REPO
git pull

echo "Removing the remote origin, for safety"
git remote rm origin

echo "Filtering by the sub-directory and moving it into the main repo directory"
git filter-branch --tag-name-filter cat --prune-empty --subdirectory-filter $FOLDER master -- -all -- --tags

echo "\n\nNow you can add a new remote to this repo. Don't forget to push with --tags!!"