1

Simple and fast question:

kevin@pc:/usr/lib/jvm$ ls -l
total 8
lrwxrwxrwx 1 root root   25 Feb 20 17:31 default-java -> java-1.11.0-openjdk-amd64
lrwxrwxrwx 1 root root   21 Apr 23 20:34 java-1.11.0-openjdk-amd64 -> java-11-openjdk-amd64
drwxr-xr-x 7 root root 4096 Jun 12 15:25 java-11-openjdk-amd64
drwxr-xr-x 8  668  668 4096 Jun 12 12:12 jdk-11.0.3

Who/what is this 668 user?? I'm the only one using this machine.

cat /etc/passwd | grep 668

Doesn't show anything with the number 668

Additional info: I installed jdk-11.0.3_linux-x64_bin.deb via GUI

  • 1
    I'm tempted to say somebody ran chown 668 instead of chmod 668 but that doesn't really add up. – Panki Jun 13 at 12:24
  • @JeffSchaller I just double clicked on jdk-11.0.3_linux-x64_bin.deb and installed it via GUI – Kevin Jun 13 at 12:31
3

I believe what you are seeing is files / directories belonging to a non-existent user. Linux mostly uses numbers to represent users rather than names usernames are effectively a lookup to a number. If the UID (number) doesn't exist in /etc/passwd (or other nsswitch mechanisms) this won't prevent files from belonging to that numeric userid.

Examples of causes include:

  • At some stage there may have been a user with uid 668, but that user has since been deleted.
  • Extracting an archive which uses UID's not names (eg tar file).
  • Simply setting the ownership with chown
  • Plugging a hard drive from another computer
  • 1
    Or the files have been extracted from some archive, preserving the UID stored in the archive. – Kusalananda Jun 13 at 12:26
  • 1
    @Kusalananda Now I think of it there's a massive number of reasons this can happen. No point in listing them all, but might as well give some examples. – Philip Couling Jun 13 at 12:30

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