> First, what command and options should I be using to create the userid w/ a
> home directory and whatever else may be needed, along with the superuser
> attributes?

 useradd -m <userid> 
passwd <userid>
add <userid> to /etc/sudoers

-m creates the user's home dir.  If these ids are going to be temporary, add -e 
to the useradd command and specify an expiration date so they automatically go 
locked when the class is over. 

You're dealing with two things here: real and effective uids. Each user 
normally must have a single unique numeric uid that should be unique across all 
systems. This is stored in /etc/passwd, and is known as their real uid (the one 
that determines permanent file ownership, etc). The _effective_ uid is the one 
that is used when executing programs, etc at the time of execution.  Normally 
the real and effective uid are the same, producing no special powers.   'su' 
(and by extension, sudo and a an appropriate filter) temporarily change the 
effective uid for that user in that process context to 0, temporarily giving 
them powers beyond the mortal *for the duration of that process context*.

 In the case of sudo, a new process context is created, the command is parsed, 
and then checked against the patterns in /etc/sudoers. If the command matches a 
pattern in /etc/sudoers, sudo temporarily changes the effective uid of the 
process to 0, does the command, and immediately changes the effective uid back 
to the real uid when the command is completed and before the user is given 
control again.  If the command is an interactive command like a shell 
(remember, Unix shells are just programs), the process retains the superuser 
privilege until the original shell started by sudo exits, and other commands 
issued from that shell inherit the Powers of Darkness from the 'sudo bash' 
command. 

These days, sudo is the way to go if you have multiple administrators who need 
superuser access. Much safer, and you don't ever have to give anyone the REAL 
root password (as you do with su) -- they authenticate with their OWN password 
before anything dangerous happens, effectively making them directly responsible 
for what they do. 

> Third, how do I list the userid after it's created?

cat /etc/passwd | grep <userid>

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