Xubuntu 14.04

I tried to 'sudo chown root' a file, and double-clicking it resulted in a "permission denied" output. I tried it again with another file, but this time nothing happened. I could click and open the file as if I had never issued the command.

A related problem is when I issue this command at directories. It takes on the x on the folder in nautilus, but I can open the directory without getting the "permission denied" warning. I don't want the directory to be openable from nautilus at all, and I'd like it to require the root password if access is attempted through terminal.

Thanks very much
Matt

Chances are the file/dir still has read permission for "other", and/or it still belongs to a group that your user is a member of which has read permission. Instead of "chown root file", use "chown root:root file", that will change both the owner and the group to root. Next use "chmod o-rwx file" to remove read, write, and execute permission for others.