Privately fork a repo

git-private-fork.sh

#!/usr/bin/env zsh

# Make sure to create a private blank repository to use as the "fork_url"
# https://gist.github.com/0xjac/85097472043b697ab57ba1b1c7530274
# @example
#   git-private-fork <upstream-url> <your-fork-url> <directory-name>
#   git-private-fork https://github.com/konnorrogers/repo.git https://github.com/billybob/fork.git ./my-fork
#
git-private-fork () {
  base_url="$1"
  fork_url="$2"
  directory="$3"

  # https://unix.stackexchange.com/questions/30091/fix-or-alternative-for-mktemp-in-os-x
  tmp_dir=$(mktemp -d 2>/dev/null || mktemp -d -t 'tmp_dir')

  # Clone then push to the fork url
  git clone --bare "$base_url" "$tmp_dir"
  cd "$tmp_dir"
  git push --mirror "$fork_url"

  # Go back to start
  cd -

  git clone "$fork_url" "$directory"

  cd "$directory"

  # Add the upstream, and disable pushing to to it.
  git remote add upstream "$base_url"

  echo "Disabling pushing to upstream..."
  git remote set-url --push upstream DISABLE

  echo "Fork complete. To grab changes from upstream do:"
  echo "git fetch upstream"
  echo "git rebase upstream/master"
}