基于@pankijs的回答，我提出了两个git别名：

Based on @pankijs answer, I made two git aliases:

[alias]
    # Delete all local branches but master and the current one, only if they are fully merged with master.
    br-delete-useless = "!f(){\
        git branch | grep -v "master" | grep -v ^* | xargs git branch -d;\
    }; f"
    # Delete all local branches but master and the current one.
    br-delete-useless-force = "!f(){\
        git branch | grep -v "master" | grep -v ^* | xargs git branch -D;\
    }; f"

添加到〜/ .gitconfig

@torek指出：

请注意，小写 -d 不会删除非完全合并分支（请参阅文档）。使用 -D 会删除这些分支，即使这会导致提交变为丢失。 非常小心地使用，因为这也删除了分支reflogs，所以通常的从意外删除中恢复的东西也不起作用。

Note that lowercase -d won't delete a "non fully merged" branch (see the documentation). Using -D will delete such branches, even if this causes commits to become "lost"; use this with great care, as this deletes the branch reflogs as well, so that the usual "recover from accidental deletion" stuff does not work either.

基本上，如果你不确定你不会失去任何重要的东西，那么千万不要使用 -force 版本。因为它永远 。

Basically, never use the -force version if you're not 300% sure you won't loose anything important. Because it's lost forever.