Section: Inspection Functions
who
function indicates the size and type of the variable as well as 
if it is a global or persistent.  There are two formats for the 
function call.  The first is the explicit form, in which a list
of variables are provided:
whos a1 a2 ...
In the second form
whos
the whos function lists all variables defined in the current 
context (as well as global and persistent variables). Note that
there are two alternate forms for calling the whos function:
whos 'a1' 'a2' ...
and
  whos('a1','a2',...)