We all have something similar, it seems! I stole mine from https://stackoverflow.com/questions/7726949/remove-tracking-....

I also set mine up to run on `git checkout master` so that I don't really have to think about it too hard -- it just runs automagically. `gcm` has now become muscle memory for me.

  alias gcm=$'git checkout master || git checkout main && git pull && git remote prune origin && git branch -vv | grep \': gone]\'|  grep -v "\*" | awk \'{ print $1; }\' | xargs -r git branch -D'