[CentOS] Utility to zero unused blocks on disk

[m.roth at 5-cent.us]

Chris Murphy wrote:
> DBAN is obsolete. NIST 800-88 for some time now says to use secure erase
> or enhanced security erase or crypto erase if supported.
>
> Other options do not erase data in remapped sectors.

dban doesn't? What F/OSS does "secure erase"? And does it do what dban's
DoD 5220.22-M does?

       mark, overkill