extract a specific path from git repository with history

extract-git-path.sh

#!/bin/bash

git clone https://example.com/repo

# change into repository dir
cd repo

git checkout --detach

# delete all local branches
git branch | grep --invert-match "*" | xargs git branch -D

# checkout all branches to extract
git branch --remotes --no-color | grep --invert-match "\->" | while read remote; do git checkout --track "$remote"; done;

# remove origin
git remote remove origin

# extract only choosen-subdirectory
# keep tag names
git filter-branch --prune-empty --subdirectory-filter choosen-subdirectory --tag-name-filter cat -- --all

rm -rf .git/refs/original/*

# delete all local tags
git tag -l | xargs git tag -d

# use BFG to clean big objects fast
# https://rtyley.github.io/bfg-repo-cleaner/

# physically delete objects from repository
# git reflog expire --expire=now --all
# git gc --prune=now