This is htop, an interactive process viewer.

Comparison between 'htop' and 'top'
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 * In 'htop' you can scroll the list vertically and horizontally
   to see all processes and full command lines.
 * In 'top' you are subject to a delay for each unassigned
   key you press (especially annoying when multi-key escape
   sequences are triggered by accident).
 * 'htop' starts faster ('top' seems to collect data for a while
   before displaying anything).
 * In 'htop' you don't need to type the process number to
   kill a process, in 'top' you do.
 * In 'htop' you don't need to type the process number or
   the priority value to renice a process, in 'top' you do.
 * In 'htop' you can kill multiple processes at once.
 * 'top' is older, hence, more tested.