#!/bin/bash

if (( $# < 3 ))
then
    echo "Usage:   $0 </path/to/repo/> <directory/to/extract/> <newName>"
    echo
    echo "Example: $0 /Projects/42.git first/answer/ firstAnswer"
    exit 1
fi


clone=$PWD/${3}Clone
newN=$PWD/${3}
git clone --no-hardlinks file://$1 ${clone}
cd ${clone}

git filter-branch --subdirectory-filter $2  --prune-empty --tag-name-filter cat -- --all
cd -
git clone file://${clone} ${newN}
cd ${newN}

git reflog expire --expire=now --all
git repack -ad
git gc --prune=now