Apple Hard Drive

I've got my boot disk partitioned in 3 partitions, one of them I was using as the mount point for OS X.  Having installed OS X successfully on my 2nd partition, I wiped the third clean.  Is there any way to nondestructively rejoin these partitions in single user mode? (ie, Does resizeVolume have an appropriate comand?)

I was about to say 'yes it's easy' when I realised I'd accidentally stepped into an Apple thread, at which point I walked away chuckling and saying 'Lol Macusers'