top(1) -o %MEM -c -d 2
display Linux tasks
-d : Delay time interval as:  -d ss.tt (seconds.tenths)
     Specifies  the delay between screen updates, and overrides the corresponding value in one's personal
     configuration file or the startup  default.   Later  this  can  be  changed  with  the  'd'  or  's'
     interactive commands.

     Fractional  seconds  are honored, but a negative number is not allowed.  In all cases, however, such
     changes are prohibited if top is  running  in  'Secure  mode',  except  for  root  (unless  the  's'
     command-line  option  was  used).   For additional information on 'Secure mode' see topic 5a. SYSTEM
     Configuration File.
source manpages: top