Create a new repository from the branch of an existing one. Wipe out git history.

new-repo-from-branch.sh

# shellcheck shell=bash
# shellcheck disable=2001
#
# If using this as zsh function snippet, remove the .sh file extension

# Creates a new repository from the branch of an existing repository
# All git history is removed
# $1: git url of the original repository to use to create a new repository from
# $2: branch name of the original repository to use
# $3: name of the new repository including the github user name. This repository must already exist in github.
#    For example: apolopena/gitpod-laravel-starter
# $4: optional commit message to use.

main() {
  local url branch new_repo loc msg user
  url="$1"
  branch="$2"
  new_repo="$(echo "$3" | awk -F/ '{print $2}')"
  loc="$(echo "$1" | sed 's/\.[^.]*$//')"
  if [[ -z "$4" ]]; then
    msg="Initial commit built from the $branch branch of $loc"
  else
    msg="$4"
  fi
  user="$(echo "$3" | awk -F/ '{print $1}')"

  mkdir "$new_repo" &&
  cd "$new_repo" &&
  git clone "$url" -b "$branch" --single-branch . &&
  rm -rf .git &&
  git init &&
  git add -A &&
  git commit -m "$msg" &&
  git remote add origin "https://github.com/$user/$new_repo.git" &&
  git branch -m main &&
  git push -u origin main
}
main "$@"