Much more complicated than necessary. I just use

git branch | xargs git branch -d

Don't quote me, that's off the top of my head.

It won't delete unmerged branches by default. The line with the marker for the current branch throws an error but it does no harm. And I just run it with `develop` checked out. If I delete develop by accident I can recreate it from origin/develop.

Sometimes I intentionally delete develop if my develop branch is far behind the feature branch I'm on. If I don't and I have to switch to a really old develop and pull before merging in my feature branch, it creates unnecessary churn on my files and makes my IDE waste time trying to build the obsolete stuff. And depending how obsolete it is and what files have changed, it can be disruptive to the IDE.