Gpart
From wikinotes
gpart is a BSD tool for working with partition tables. Similar to linux's fdisk.
camcontrol devlist # list all devices
gpart list # print all disks (with gpt partition tables)
fstyp /dev/da0s1 # detect filesystem type
gpart show /dev/da0 # print partition table for da0
# create/destroy partition table
sudo gpart destroy -F da1
gpart create -s gpt /dev/da0
# create partitions
gpart add -s 160G -t freebsd-ufs /dev/da0
newfs -U da0p1 # create new ufs filesystem on da0p1