Check out multiple branches simultaneously with git worktree add

Documented steps

1. Choose a new directory path for the second working tree and run `git worktree add <path>` to check out the current branch there; or `git worktree add <path> <branch>` to check out an existing branch.
2. To create a new branch in the new worktree, use `git worktree add -b <new-branch> <path>` (the simplest form `git worktree add <path>` auto-creates a branch named after the path's last component).
3. For a throwaway detached checkout, run `git worktree add -d <path>` to create a detached HEAD at the current commit.
4. List all worktrees with `git worktree list` (or `--porcelain` for a stable script-friendly format).
5. Switch between working trees by cd-ing into each directory; they are independent checkouts sharing the same repository objects and refs.
6. Remove a worktree with `git worktree remove <path>` (only clean worktrees are removed without `--force`; the main worktree can never be removed).
7. Clean up stale administrative entries after a worktree was deleted out-of-band with `git worktree prune`.
8. Official docs: https://git-scm.com/docs/git-worktree