Random file of set length

\_ SMTP quoth Gilbert T. Gutierrez, Jr. on 9/11/2002 15:35 as having spake thusly:
\_
\_ I want to create a random file of 5MB. How do I do that?

dd bs=5242880 count=1 if=/dev/random of=/tmp/my5M

or something like that?

YMMV.

David