git 如何恢复上次提交的文件

git reset <commit>更改HEAD指向的位置，但不会将文件还原为该提交时的状态。如果要将文件还原为提交时的外观，则需要git reset --hard <commit>

关于三种重置模式：

       --soft
           Does not touch the index file or the working tree at all (but
           resets the head to <commit>, just like all modes do). This
           leaves all your changed files "Changes to be committed", as git
           status would put it.

       --mixed
           Resets the index but not the working tree (i.e., the changed
           files are preserved but not marked for commit) and reports what
           has not been updated. This is the default action.

           If -N is specified, removed paths are marked as intent-to-add
           (see git-add(1)).

       --hard
           Resets the index and working tree. Any changes to tracked files
           in the working tree since <commit> are discarded.