Search code examples
linuxbashshelldirectory-structurecd

What does double slash // in `cd //` mean in Linux?

I've entered a command cd // instead of cd / by mistake and instead of getting an error as I'd expect the shell (Bash) showed a prompt as if I'm in the // directory:-

<username>@<hostname>://$
<username>@<hostname>://$ pwd
//

Listing the content of the directory shows that it is the same as /.

So what exactly cd // do and what's the difference from cd /?

Solution

  • Actually it means nothing and is ignored.

    From the Bash FAQ E10::

    E10) Why does 'cd //' leave $PWD as '//'?

    POSIX.2, in its description of 'cd', says that three or more leading slashes may be replaced with a single slash when canonicalizing the current working directory.

    This is, I presume, for historical compatibility. Certain versions of Unix, and early network file systems, used paths of the form //hostname/path to access 'path' on server 'hostname'.

    Also the Unix standards states:

    A pathname that begins with two successive slashes may be interpreted in an implementation-defined manner, although more than two leading slashes shall be treated as a single slash.