(C-a S, C-a |)
Split the current region into two new ones. All regions on the
display are resized to make room for the new region. The blank
window is displayed in the new region. The default is to create
a horizontal split, putting the new regions on the top and
bottom of each other. Using ‘-v’ will create a vertical split,
causing the new regions to appear side by side of each other.
Use the remove or the only command to delete regions.
Use focus to toggle between regions.
When a region is split opposite of how it was previously split
(that is, vertical then horizontal or horizontal then vertical),
a new layer is created. The layer is used to group together the
regions that are split the same. Normally, as a user, you should
not see nor have to worry about layers, but they will affect how
some commands (focus and resize) behave.
With this current implementation of screen, scrolling data
will appear much slower in a vertically split region than one
that is not. This should be taken into consideration if you need
to use system commands such as cat or tail -f.