git branch -m <oldname> <newname>可以把branch重命名。例如:

[root@localhost test_git]# git branch
  master
* new
[root@localhost test_git]# git branch -m new new1
[root@localhost test_git]# git branch
  master
* new1

如果要重命名的就是当前branch,可以省略<oldname>

[root@localhost test_git]# git branch -m new2
[root@localhost test_git]# git branch
  master
* new2