Self-tutoring about Ubuntu: the tutor mentions sudo.
In Linux, some tasks require elevated privileges. Trying to do such an action without assuming elevated privilege (sudo in Ubuntu) may lead to an error. The system is designed to prevent less-privileged users from making unauthorized changes. (Typically, to take on the sudo role, the user needs to enter a password.)
If a user has that privilege, but forgets to invoke it before a command that requires it, the user may not be reminded. In such a case, an error may be reported which seems nothing to do with lacking sudo privilege. Yet, the reason might just be that they didn’t assume the elevated privilege (sudo). At least, that seems to be my experience.Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.