Open a terminal and do the following:
1. type whoami
Q1: What is the result?
2. type id -un
Q2: what is the result?
3. type echo $LOGNAME
Q3: what is the result?
Q4: Why do these three commands return the result they do? Do all of the tools retrieve the information from the same place?
4. type id -a
Q5: what are the results? are the results just for your user or for all users?