Git remove all branches except m

If you use git push --set-upstream someBranch to push a branch to remote, then these branches are merged, you do git branch -a, you may find a lot of branches, which is ugly.
git branch shows local branches.
git branch -r shows remote branches.
git branch -a shows all branches.

$ git branch -a
* master
  optimize_by_regex
  optimize_map_store_method
  optimize_use_rect
  remotes/origin/dev
  remotes/origin/master
  remotes/origin/optimize_beautify_setup
  remotes/origin/optimize_beautify_setup_init_method
  remotes/origin/optimize_by_regex
  remotes/origin/optimize_map_store_method
  remotes/origin/optimize_use_rect

• First, I'd like to remove all local branches except master:
  • Have a check by:

$ git branch | grep -v -E *master*
  optimize_by_regex
  optimize_map_store_method
  optimize_use_rect

And yes, these are exactly the branches you want to remove, so:

$ git branch -D `git branch | grep -v -E *master*`
Deleted branch optimize_by_regex (was a69df33).
Deleted branch optimize_map_store_method (was 94be07e).
Deleted branch optimize_use_rect (was 6810a37).

• Check what have been removed, and what have remained:

$ git branch -a
* master
  remotes/origin/dev
  remotes/origin/master
  remotes/origin/optimize_beautify_setup
  remotes/origin/optimize_beautify_setup_init_method
  remotes/origin/optimize_by_regex
  remotes/origin/optimize_map_store_method
  remotes/origin/optimize_use_rect

• Second, remove all remote branches except master:
  • Have a check by:

$ git branch -r | grep origin | grep -v -E *master* | grep -v HEAD | cut -d/ -f2 | while read line; do echo $line; done
dev
optimize_beautify_setup
optimize_beautify_setup_init_method
optimize_by_regex
optimize_map_store_method
optimize_use_rect

And if these are exactly the branches to be deleted:

$ git branch -r | grep origin | grep -v -E *master* | grep -v HEAD | cut -d/ -f2 | while read line; do git push origin --delete $line;done
To XXX.git
 - [deleted]         dev
To XXX.git
 - [deleted]         optimize_beautify_setup
To XXX.git
 - [deleted]         optimize_beautify_setup_init_method
error: unable to delete 'optimize_by_regex': remote ref does not exist
error: failed to push some refs to 'XXX.git'
To XXX.git
 - [deleted]         optimize_map_store_method
error: unable to delete 'optimize_use_rect': remote ref does not exist
error: failed to push some refs to 'XXX.git'

If remote branch delete successfully,

To XXX.git
 - [deleted]         dev

else:

error: unable to delete 'optimize_use_rect': remote ref does not exist
error: failed to push some refs to 'XXX.git'

This is weird, do some sync:

$ git fetch --all --prune
Fetching origin
From XXX
 - [deleted]         (none)     -> origin/optimize_by_regex
 - [deleted]         (none)     -> origin/optimize_use_rect

Refer to:

git-fetch - Download objects and refs from another repository

git fetch [<options>] [<repository> [<refspec>…​]]
git fetch [<options>] <group>
git fetch --multiple [<options>] [(<repository> | <group>)…​]
git fetch --all [<options>]

--all
Fetch all remotes.

-p
--prune
Before fetching, remove any remote-tracking references that no longer exist on the remote. Tags are not subject to pruning if they are fetched only because of the default tag auto-following or due to a --tags option. However, if tags are fetched due to an explicit refspec (either on the command line or in the remote configuration, for example if the remote was cloned with the --mirror option), then they are also subject to pruning. Supplying --prune-tags is a shorthand for providing the tag refspec.

See the PRUNING section below for more details.

PRUNING
Git has a default disposition of keeping data unless it’s explicitly thrown away; this extends to holding onto local references to branches on remotes that have themselves deleted those branches.

If left to accumulate, these stale references might make performance worse on big and busy repos that have a lot of branch churn, and e.g. make the output of commands like git branch -a --contains <commit> needlessly verbose, as well as impacting anything else that’ll work with the complete set of known references.

git-fetch.

• Finally,

$ git branch -a
* master
  remotes/origin/master