Maybe this will sound like dumb question but the way i'm trying to do it doesn't work.
I'm on livecd, drive is unmounted, etc.
When i do backup this way
sudo dd if=/dev/sda2 of=/media/disk/sda2-backup-10august09.ext3 bs=64k
...normally it would work but i don't have enough space on external hd i'm copying to (it ALMOST fits into it). So I wanted to compress this way
sudo dd if=/dev/sda2 | gzip > /media/disk/sda2-backup-10august09.gz
...but i got permissions denied. I don't understand.