Here's my take on the one-liner that I use via a `git tidy` alias[1]. A few points:
* It ensures the default branch is not deleted (main, master)
* It does not touch the current branch
* It does not touch the branch in a different worktree[2]
* It also works with non-merge repos by deleting the local branches that are gone on the remote
git branch --merged "$(git config init.defaultBranch)" \
| grep -Fv "$(git config init.defaultBranch)" \
| grep -vF '*' \
| grep -vF '+' \
| xargs git branch -d \
&& git fetch \
&& git remote prune origin \
&& git branch -v \
| grep -F '[gone]' \
| grep -vF '*' \
| grep -vF '+' \
| awk '{print $1}' \
| xargs git branch -D
[1]: https://github.com/fphilipe/dotfiles/blob/ba9187d7c895e44c35...This is a good one you should contribute it to git extras.
The use of init.defaultBranch here is really problematic, because different repositories may use a different name for their default, and this is a global (your home directory scope) setting you have to pre-set.
I have an alias I use called git default which works like this:
then it becomes This figures out the actual default from the origin.