WHO DO CMD OPTIONS

a       all (bdlprtu options)
b       boot time
d       dead processes
H       print header
l       login processes
n #     specify number of users per line for -q
p       processes other than getty or users
q       quick who
r       run level
s       short form of who (no time since last output or pid)
t       time changes
T       status of tty (+ writable, - not writable, ? hung)
u       useful information
=
Display all information
who -Ha
Dead Process
who -Hd
Number of users
who -Hq
Terminal Status
who -HT
who is doing what
whodo