0

I stupidly ran this command in Ubuntu 18.04:

sudo chown -R $USER:$USER /usr

Now I want to undo this but when I run:

chown -R root:root /usr

I get this error:

operation not permitted

And I can't run a sudo command and gives me this error:

/usr/bin/sudo must be owned by uid 0 and setuid bit set

How can I fix this?

Kulfy
  • 17,416
  • 26
  • 64
  • 103
fjahan
  • 1
  • 1
    Reboot in [recovery mode](https://wiki.ubuntu.com/RecoveryMode). – Jos May 16 '19 at 08:22
  • @Kulfy The accepted answer to that question suggests to completely reinstall Ubuntu, which is overkill. – Jos May 16 '19 at 08:30
  • Iam facing a deadline isn't any other way except reinstalling? – fjahan May 16 '19 at 08:36
  • @Jos In what way is the accepted answer "overkill"? I checked and there are 13 different `[UID,GID]` pairs on my `/usr`. – waltinator May 16 '19 at 13:33
  • @waltinator Hm. All four of my systems have only `/usr/bin/at` as the exception (daemon:daemon). But I realize I simply assumed that the whole of `/usr` was owned by root. – Jos May 16 '19 at 14:44
  • @Jos It's difficult to determine and replicate the original schema, I think. – Kulfy May 16 '19 at 15:33

1 Answers1

2

You have to boot in maintenance (recovery) mode or with live CD / USB and mount the root volume.

FedKad
  • 9,212
  • 7
  • 40
  • 79
  • Can you give more details of how to fix this in recovery mode? – fjahan May 16 '19 at 08:30
  • See the link I provided. After step 9, enter your `chown -R root:root /usr` and reboot. – Jos May 16 '19 at 08:59
  • That won't fix the files owned by `root`, but in one of the `cricket`, `crontab`, `dip`, `mail`, `messagebus`, `mlocate`, `postdrop`, `shadow`, `ssh`, `tty` or `utmp` groups. Many strange failures are in your future. – waltinator May 16 '19 at 17:24