If you use linux, you must have run into the dd command at some point in time.

On most distributions, dd and ddrescue come standard, and with these simple tools, you can zero a disk partition or even copy a disk directly.

For example, in order to copy a disk using dd:

$ dd if=/dev/sda of=/dev/sdb 


$ ddrescue -v --force /dev/sda /dev/sdb

I prefer the second as it will show you the current status.

Other options include using a clonezilla cd which works on multiple platforms, and also allows you to boot to a shell and issue the above commands if needed.