This little script migh help you along the way as it covers the important ones. You will have to change it slightly to meet your needs.
for i in `ifconfig -a | egrep "^eri" | awk '/^[a-z]*[0-9]*: / {print $1}' | sed s/://`
do
device=`echo $i | sed s/[0-9]*$//`
instance=0
ndd -set /dev/$device instance $instance
duplex=`ndd -get /dev/$device link_mode`
speed=`ndd -get /dev/$device link_speed`
autoneg=`ndd -get /dev/$device adv_autoneg_cap`
case "$speed" in
"0"

echo "$i is at 10 mbit \c";;
"1"

echo "$i is at 100 mbit \c";;
*) echo "$i is at ??? mbit \c";;
esac
case "$duplex" in
"0"

echo "half duplex \c";;
"1"

echo "full duplex \c";;
*) echo "??? duplex \c";;
esac
case "$autoneg" in
"0"

echo "with auto negotiation";;
"1"

echo "without auto negotiation";;
*) echo "??? auto negotiation";;
esac
done