Hi, I am selling one of my computers and would like to wipe the hard drive before selling. I found some instructions here:
using the wipe command.

I just have one question. When I do 'sudo fdisk -l' to list the drives I see 3 drives (/dev/sdaX) where X=1,2,5. These drives correspond to 'Linux', 'Extended', and 'Linux swap /Solaris', respectively. The latter two correspond to about 2M blocks, whereas the Linux drive is much larger. When I wipe the drive, should I just do /dev/sda1, or should I do them all?