# create a simple linear

mdadm -CR $md0 -l linear -n3 $dev0 $dev1 $dev2
check linear
testdev $md0 3 $mdsize0 64 
mdadm -S $md0

# now with version-1 superblock
mdadm -CR $md0 -e1 --level=linear -n4 $dev0 $dev1 $dev2 $dev3
check linear
testdev $md0 4 $mdsize1 64 
mdadm -S $md0

# now with no superblock
mdadm -B $md0 -l linear -n5 $dev0 $dev1 $dev2 $dev3 $dev4 
check linear
testdev $md0 5 $size 64
mdadm -S $md0