learned about rwho, who, write

After SSH-ing into the campus computers, can look at other users on the system
ssh username@pc10.cs.ucdavis.edu
rwho
// lists all users on the csif machines

who pc 9
// lists all users on pc 9

who
// lists all users on current pc

write person
// must ssh to same computer as person, then writes stuff to their cmd prompt.