Copy data/partition with dd: you can just copy files and partions but NO folders.

dd if=/path/file of=/path/file 
dd if=/dev/sda1 of=boot.partition 
dd if=/dev/sda of=/tmp/mbr_copy bs=512 count=1
dd if=/dev/cciss/c0d0 bs=16065b | gzip -1 >/mnt/LinuxDD_Images/wilde20110416.gz

dd if=/dev/zero of=youroutputfile bs=1024 count=102400                               #Creates a file with blocksize 1024 and 100 MB
dd if=/dev/zero of=/tmp/swapfile bs=1024 count=2M                                    #Creates a file with blocksize 1024 and 2GB