split

split -b 400M king_of_ring.avi

split -b 400m king_of_ring.avi king_of_ring_part_

split -b 400m -d king_of_ring.avi king_of_ring_part_

split -d -10 /etc/passwd my_passwd_

md5sum king_of_ring.avi

cat xaa xab > king_of_ring_merge.avi