$ZPROM[PT] contains a string value specifying the current Direct Mode prompt. By default, GTM>is the Direct Mode prompt. M routines can modify $ZPROMPT by means of a SET command. $ZPROMPT cannot exceed 16 characters. If an attempt is made to assign $ZPROMPT to a longer string, only the first 16 characters will be taken.
In UTF-8 mode, if the 31st byte is not the end of a valid UTF-8 character, GT.M truncates the $ZPROMPT value at the end of last character that completely fits within the 31 byte limit.
The environment gtm_prompt initializes $ZPROMPT at process startup.
GTM>set $zprompt="Test01">" Test01>set $zprompt="GTM>"
This example changes the GT.M prompt to Test01> and then back to GTM>.