Judging by your title, you want to copy a whole partition to another partition, or to a file in another partition?
dd (Data Dump) should do this:
Code:
dd -if=/dev/hda1 -of=/dev/hdb1
(or)
dd -if=/dev/hda1 -of=~/hda1.bak
where /dev/hda1 is the partition you're copying from, and /dev/hdb1 or ~/hda1.bak is partition or file, respectively, that you're copying to.
If the source medium has errors, you'll want to see
my own thread, which at the time of writing is just a little further down this very forum.