Linux doesn't provide a straight forward command to list all users in the system. You can list users who are currently logged in, you can find.
MySQL FAQ: How do I show the users I've created in a MySQL database, including MySQL user permission information?...
Show user lynsfunaspx -- journey Seoul
I think it may be necessary to group on User too, to only get unique user values, since there's a seperate row for each user host entry. So you can see why I need to ask for your help.
Show user lynsfunaspx going