On just about any modern Linux system, you don't get much better than the ATA Secure Erase command (assuming you're using an ATA drive - USB enclosures don't work). You send the command to the drive and the drive self-obliterates (which is important because EVERYTHING is gone on the drive, so if you have a Windows partition on the same drive it would be gone too). It's also more effective on SSDs than DBAN would be.
https://ata.wiki.kernel.org/index.php/ATA_Secure_Erase
Note that on just about every system I have, the bios locks the drive so this can't be done until you do the suspend to ram trick mentioned in step 1a of the guide above. And of course, this will take some time on a mechanical harddrive. On my SSDs', it'll wipe 200 gig in less than 5 minutes. It also should go without saying make sure you pick the right drive (I'd unplug drives you DON'T want wiped). As there isn't a way back from this as far as I know. That's kinda the point.