Git: How to find all branches that were never merged back into master

Question

We have a fairly large GIT repo and I would like to remove branches that were never merged back into master.

The reverse is fine too - a way to list all branches tha

Answer 1

git help branch says:

   With --contains, shows only the branches that contain the named commit
   (in other words, the branches whose tip commits are descendants of the
   named commit). With --merged, only branches merged into the named
   commit (i.e. the branches whose tip commits are reachable from the
   named commit) will be listed. With --no-merged only branches not merged
   into the named commit will be listed. If the  argument is
   missing it defaults to HEAD (i.e. the tip of the current branch).

Hence, for finding all branches already merged to master you can use git branch --merged master.