I have an external hard drive which both Ubuntu and Microsoft Windows can access (I'm pretty sure I used FAT or something). Anyway at the command prompt:

ls -l on the root level of the hard-drive.

What's weird is the owner is my Ubuntu user called ub_user and the group permissions are a random UID that doesn't resolve...

So I thought I could fix it by doing a chown -R ub_user:ub_user * on the hard drive and now ub_user has group permissions as well as the weird UID.

Super confused. Didn't know there could be multiple group ownership of a file.

Is this coming from Windows?

Is there any way for me to get rid of the random UID users? Should I or will it break everything?

Example line:

ll Whiplash.mp4

-rw-r--r-- 1 ub_user ub_user 1767846558 Oct 22 2015 Whiplash.mp4

What is 1767846558?

  • Can you post an example ll line? I'm not quite sure what you mean...
    – Kaz Wolfe
    Dec 30 '16 at 20:00
  • By the way: if you did use FAT, then the owner metadata is fake anyway. FAT has no concept of file owner; after all, it was created for operating systems that don't even have a concept of users. You can tell the filesystem driver when you mount the filesystem which user and group it should report to the OS; typically it will "pretend" all files are owned by the user who mounted the filesystem. Dec 31 '16 at 0:36

With the following:

-rw-r--r-- 1 ub_user ub_user 1767846558 Oct 22 2015 Whiplash.mp4

1767846558 is not a weird UID. It's the file size.


Files in (most) Linux filesystems have only one owning group/user.

As mentioned in your question, the following line can be parsed:

-rw-r--r-- 1 ub_user ub_user 1767846558 Oct 22 2015 Whiplash.mp4
  • -rw-r--r--: File, owner had read/write, all others have read-only.
  • 1: The file has only one link (itself) attached to it.
  • ub_user: The file is owned by the user ub_user.
  • ub_user: The file is owned by the group ub_user.
  • 1767846558: The file is 1767846558 bytes in size.
  • Oct 22 2015: The file was made on October 22, 2015.
  • Whiplash.mp4: The file is called Whiplash.mp4.

If you instead call ls -lh on the file, you'll notice that your output would read something similar to:

-rw-r--r-- 1 ub_user ub_user 1.7G Oct 22 2015 Whiplash.mp4

Reflecting the fact that the file is about 1.7 GB in size.

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