There is a runtime configuration variable called SCREEN that controls many features of the video sub-system. This option works in the same manner as the KEYBOARD variable. You can specify one or more SCREEN variables. Attributes that you can set are identified by one or more sets of keywords and associated values, separated from each other by spaces or tabs; the syntax is:
SCREEN keyword=value [keyword=value]...
The following keywords are supported:
| ALPHA-UPDATES=value | CONVERT-OUTPUT=value |
| EDITED-UPDATES=value | ERROR-BELL=value |
| ERROR-BOX=value | ERROR-COLOR=value |
| ERROR-LINE=value | FORM-FEED=value |
| INPUT-DISPLAY=value | INPUT-MODE=value |
| JUSTIFY=value | NUMERIC-UPDATES=value |
| PROMPT=value | PROMPT-ALL=value |
| PROMPT-ATTR=value | REFRESH-LINES=value |
| REFRESH-MODE=value | SHADOW-STYLE=value |
| SIZE=value | WINDOW=value |
These keywords are described in detail below.