**screen** is a unix command that manages few virtual terminals.

Splitting the screen
--------------------

Start screen with few terminals and use C-a S for splitting the current view. C-a TAB allows moving from one to another view.

  So::

    C-a S split the screen
    C-a TAB move to another view

man page:
http://www.sunsite.ualberta.ca/Documentation/Gnu/screen-3.9.4/html_chapter/screen_toc.html

Thanks to Gwenn aka demisel.