A display name on Unix has the following syntax:
If hostname is omitted this refers to a display on the same
machine as the client is running on. A Unix socket is used to connect
to the display identified by
displayno, which must be an integer
from 0 and upwards.
If hostname is specified, it gives the network name or IP-number of the machine to contact. A TCP socket is used, connecting to port 6000+displayno on hostname.
If the display contains more than one screen, screenno can be specified to make another screen than 0 the default screen. If the number is larger than the available maximum screen number, it will be set to the maximum.
A few examples:
:0 Display 0 on this host, connects to the Unix socket /tmp/.X11-unix/X0 :0.1 Same as above, but specifying a different default screen myhost:0 Display 0 on myhost, connects to TCP port 6000 myhost:10 Display 10 on myhost, connects to TCP port 6010 localhost:0 Display 0 on localhost, i.e. the same host as the client runs on. Uses a TCP socket, while :0 uses a Unix socket
The default display name is stored in the environmental variable
DISPLAY. If that isn't set,
Go to the first, previous, next, last section, table of contents.