Shorter version:
Code:
ifconfig $(netstat -rf inet | awk '{if ($1 == "default") print $6}') inet | awk '{if ($1 == "inet") print $2}'

or $PATH-independently:
Code:
/sbin/ifconfig $(/usr/sbin/netstat -rf inet | /usr/bin/awk '{if ($1 == "default") print $6}') inet | /usr/bin/awk '{if ($1 == "inet") print $2}'