Temporarily Changing User Identity with the su Command
This first scenario requires the existence of a root account, which is not enabled by default on Ubuntu systems and is not generally recommended in the Ubuntu community. However, there are times when it makes sense. Discussing that is beyond the scope of this chapter, but for the sake of argument, for the scenario and details in this section assume we are operating in one of those special cases and that a root account has been enabled.
What if you have access to an enabled root account as a super user but are logged on as a regular user because you are performing nonadministrative tasks, and you find you need to do something that only the super user can do? The
su command is available for ...