8.6.34 Dummy files
The following commands will create dummy or empty files:
$ dd if=/dev/zero of=filename bs=1k count=5 # 5KB of zero content
$ dd if=/dev/urandom of=filename bs=1M count=7 # 7MB of random content
$ touch filename # create 0B file (if file exists, updates mtime)
For example, the following commands executed from the shell of the Debian boot
floppy will erase all the content of the hard disk /dev/hda
completely for most practical uses.
# dd if=/dev/urandom of=/dev/hda ; dd if=/dev/zero of=/dev/hda