git-update-ref

Update ref to new value

$ git update-ref [refs/heads/branch] [commit]

$ git update-ref -d [refs/heads/branch]

$ git update-ref --symbolic-ref [ref] [target]

$ git update-ref [ref] [new] [old]

git update-ref [options] ref newvalue [oldvalue]

git update-ref safely updates ref names stored in the repository. It provides atomic ref updates with optional old value verification, ensuring that a ref is only changed if it currently points to an expected value.
This is a low-level plumbing command used internally by higher-level commands like `git branch` and `git tag`.

-d

Delete ref.

Create reflog.

Don't dereference symbolic.

Reflog message.

Read from stdin.

git-symbolic-ref(1), git-branch(1)