This article will guide you on the different methods to list down all the Linux system users. To know whether a particular user is having sudo access or not, we can use -l and -U options together. For example, If the user has sudo access, it will print the level of #sudo access for that particular user.
If the user don't have sudo access, it will print that user is not allowed to run sudo on localhost.
To change users in #Linux:
The su command lets you switch the current user to any other user.
If you need to run a command as a different (non-root) user, use the –l [username] option to specify the user account.
Additionally, su can also be used to change to a different shell interpreter on the fly.
https://linuxapt.com/blog/76-how-to-list-users-in-linux
