Typing whoami will tell you whose account you are currently using. The command finger will get you information on all users currently logged onto your system. You can also find out about a single person. For example, finger smith will give you information about the user smith. Finger will make a guess for you, so you can use it to find out email addresses. Thus, finger smyth will probably give you information on smith whose name you had forgotten how to spell. You can also use finger to ask about people elsewhere on internet using their email address as in finger firstname.lastname@example.org. This doesn't work 100% of the time.
A list of your environmental variables can be obtained via setenv. The commands ps and jobs tell you the current processes and jobs that are owned by you. To get all processes try ps -elf.