Can you effectively wipe a hard drive from the current Linux OS?

Question

I have a laptop that is barely alive. The screen is busted. The power cord is frayed. The power indicator flashes red sometimes. Etc. So I want to wipe the hard drive as effectively as I can before I take it into recycling today. The usual way to do this is to boot DBAN from a flash drive, but, oh no! I don't have a spare flash drive or any CDs!

What is the most effective way to wipe data from a hard drive if one is restricted to trying to do so from the Linux OS currently installed on the drive? Or from the BIOS I suppose. I ask because I assume there is something better than

1. Classic rm -rf --no-preserve-root /.

2. dd if=/dev/zero of=/dev/sda or something related.

3. Remove and disassemble the drive with a hammer. But does that make it harder to recycle? I'm not actually sure how hard drives are recycled. :) But I'd rather not do this.

Answer 1

Use dd (aka: option 2): Simple and effective.

dd doesn't care about mounted filesystems.

It has earned its nickname "Data Destroyer" for a reason

Testing it on a virtual machine yields the results expected. Just add && poweroff to put it out of its I/O error misery.

FWIW, testing indicates poweroff is available even after dd has completely overwritten the drive; I presume Bash loads it into RAM on start.

As per @Andy's comment (while sticking with dd), overwrite the drive multiple times. Chain multiple dd commands together or use a for loop to automate it:

for ((I=0;I<=7;I++)) {
  dd if=/dev/zero of=/dev/sda status=progress;
  echo "Drive has been overwritten $I time(s)";
}