1. Git Cleaning
# clean local branches
git branch -d $(git branch --merged=master | grep -v master)
# clean local remote branches
git fetch --prune
Reference: here
2. Rename Local Branches
Say you want to rename the branch old-name to new-name locally.
git checkout old-name
git branch -m new-name
# -m: move/rename a branch and its reflog
3. Rename Local & Remote Branches
Say you want to rename the branch old-name to new-name locally, then push it to remote and delete the original remote brach.
git checkout old-name
git branch -m new-name
git push origin :old-name
# <+><source>:<destination>
# git push origin :old-name means make origin old-name empty
git push --set-upstream origin new-name