The following is a problem-report that was send to www.freebsd.org (modified):

>xorg starts with the following error message:
>"xauth: (stdin):1:  bad add command line"
>This error gets caused by the startx script. In order to
>generate a hexkey (MIT-MAGIC-COOKIE-1) for the xauth entry
>in ~/.Xauthority it uses /dev/urandom. If random
>(urandom -> random [symlink under FreeBSD-STABLE]) is not present (kernel or
>kld), the device
>node is missing and `xauth add` will fail due to a missing hexkey.

>This problem is probably also being caused by any previous
>Xorg and XFree86 port version and very likely appears on all
>FreeBSD RELENGs that use `devd` instead of the MAKEDEV system (>=RELENG_5).
>Since `sh MAKEDEV all` on older systems should take care of
>/dev/random and the link to /dev/urandom it should also be possible
>to delete the device node from /dev and experience the very same
>problems, as in RELENG_5 and higher.

This problem should occur on any OS that has a kernel that can be compiled
without a static /dev/urandom or /dev/random device. Under FreeBSD (maybe other
*BSDs) that device can be loaded from a kernel module.

It would be very nice if the startx script could check for the device existence
of /dev/urandom or /dev/random before it issues the xauth command. The error
message above is very confusing for people dealing with this problem and trying
to solve it.