no login.defs is not the right file , that's just definitions for the login program
since this is an x file
i think use something appended to x startup
so i think it depends on how you startx
and different distribution have differebt sets of scripts
my version of xinitrc automaticaly looks for a default Xmodmap with this code
Code:
usermodmap=$HOME/.Xmodmap
sysmodmap=/usr/X11R6/lib/X11/xinit/.Xmodmap
if [ -f $sysmodmap ]; then
xmodmap $sysmodmap
fi
if [ -f $usermodmap ]; then
xmodmap $usermodmap
fi
so first is to just rename it ~/.Xmodmap instaead ~/.xmodmap
and that might be all you need
might want to read your xinitrc
other candidates for running your command are
~/.xinitrc
~/.xsession
/etc/X11/xinit/xinitrc
possibly bottom of startkde would do it if you use that