c-x c-f 在寻找文件时如何返回上级目录 想要找一个上级的文件的东西，在输入 c-x c-f 之后，提示c-l可以返回上一层的目录，但是操作中却不行，求大神帮助
强推 C-x C-j (dired-jump) 。超高频使用的快捷键。
Emacs 26.3 默认没有绑定。
另外 dired＋ 有很多功能。加载它后会自动绑定，dired-jump 就会自动帮你绑定。
C-x C-j runs the command dired-jump (found in global-map), which is an interactive autoloaded compiled Lisp function in ‘dired-x.el’. It is bound to C-x C-j. (dired-jump &optional OTHER-WINDOW FILE-NAME) Jump to Dired buffer corresponding to current buffer. If in a file, Dired the current directory and move to file’s line. If in Dired already, pop up a level and goto old directory’s line. In case the proper Dired file line cannot be found, refresh the dired buffer and try again. When OTHER-WINDOW is non-nil, jump to Dired buffer in other window. When FILE-NAME is non-nil, jump to its line in Dired. Interactively with prefix argument, read FILE-NAME.