dd

Fill a device with zeros

dd if=/dev/zero of=/dev/sdb

Fill a device with 1024*10240 bytes of zeros

dd if=/dev/zero of=/dev/sdb count=10240 bs=1024

Create a random key file:

dd if=/dev/urandom of=key_file bs=1024 count=4 iflag=fullblock

awk (1) cryptsetup (1) dd (2) device (1) drive (1) encryption (2) ext (1) filesystem (1) firefox (1) grep (1) loop-back (1) losetup (1) mkfs (1) mount (1) protocol-handler (1) security (2) sed (1) ssh (3) stat (1) truncate (1) urandom (1)