In screen the terminal multiplexer.
- To split vertically:
ctrl
a
then |. - To split horizontally:
ctrl
a
thenS
(uppercase one). - To unsplit:
ctrl
a
thenQ
(uppercase one). - To switch from one to the other:
ctrl
a
thentab
Note: After splitting, you need to go into the new region and start a new session via ctrl
a
then c
before you can use that area.