MGED Environment Variables
DISPLAY
DISPLAY specifies where to draw the windows.
BRLCAD_ROOT
BRLCAD_ROOT specifies where to find the root
directory of the installed BRL-CAD package.
EDITOR
EDITOR specifies which external editor to use
when one is required.
FB_FILE
FB_FILE specifies the framebuffer to use when
using applications that require a framebuffer.
TCL_LIBRARY
TCL_LIBRARY specifies where to look for
Tcl files.
TK_LIBRARY
TK_LIBRARY specifies where to look for
Tk files.