dd

Copy a file, converting and formatting according to the options.

dd if=/dev/fd0 of=floppy.image

Copy from the "zero maker" to a file in the root of the filesystem in 20m chunks. This can be used to zero the unused sections of your harddisk to make it easier for imaging programs like g4u to compress.

dd if=/dev/zero of=/0bits bs=20971520   # bs=20m
rm /0bits