/etc/rcconf

Normally type return to get sh (Bourn shell) working.

You may need to say mount -a to mount the filesystems.

Just for example,

# mount -a
# TERM=xterm
# export TERM
# vi /etc/rc.conf

# echo my-nis-domain-name > /etc/defaultdomain
# echo 192.168.1.1 > /etc/mygate
# echo myhost      > /etc/myname
# echo inet myhost netmask 0xffffff00 media autoselect > /etc/ifconfig.gm0
# cat > /etc/resolv.conf
nameserver 192.168.1.2
domain     your.domain
^D

The files you may need to change are listed at http://www.ki.nu/software/NetBSD/macppc/after-sysinst.shtml
(seems a little bit out-of-date list, though.)