from within the %DJDIR%\info directory and after copying the grx242um.inf file there you can issue
install-info -e "* grx (grx242um). GRAPHICS" grx242um.inf dir
if you do not want to cd to that directory you may use the /dev/env/DJDIR/ syntax (valid from v2.03) i.e.
cp grx242um.inf /dev/env/DJDIR/info/grx242um.inf install-info -e "* grx (grx242um). GRAPHICS" \ /dev/env/DJDIR/info/grx242um.inf \ /dev/env/DJDIR/info/dir (I have checked) In fact in would be better to rename everywhere grx242um.inf as grx.inf (or grx.info) so that every new version replaces the old one instead of adding a new entry.
Thanks Maurice. But I don't know why it doesn't work for me, install-info run without a warning, the menu item is added, but I can not follow the link (neither info grx242um works).