As i have learnt that being a super-user in linux/ubuntu we can unlock those task which is being hide out from other user so to avoid messing with the files and directories.Now i want to know upto which extent does superuser work with files.now that i have got my phpmyadmin files in /opt/lampp/phpmyadmin i want to configure my config.inc.php i found that with a superuser i cant edit and save the changes permission deinied. so far i have done is sudo passwd root then typed in my user pass and then password for unix and confirm. now i logged in as root by su and then password. i could not edit the changes.i found with sudo nautilus i could do the task and also copy and paste files from my home directory to other partition which i created that could not be done with a SU. and 1 more thing idk but can a normal user easily change root password as its only need to type in user password.
Root can always do anything in Ubuntu!
You are probably getting a "permission denied" because the file is marked as read-only. The owner of the file (or root) can change permissions with the chmod command, or of course with Nautilus' graphical interface.
In Ubuntu, by default, the first user you create belongs to the "sudo" group, which has the possibility of becoming root by only entering their password. All this is configured via the /etc/group and /etc/sudoers files.