To secure erase when that option isn't available in Disk Utility. For example, for SSDs. Boot from another disk or recovery mode. Erase the disk encrypted, with a complex key. Fill the disk with zeros. Erase it again, without encryption or with a different key.
Options to fill with zeros
If it is available, use mkfile, otherwise use dd...
mkfile SIZE FILE Example: mkfile 200G File1 dd if=/dev/zero of=FILE bs=BLOCKSIZE count=BLOCKS Example: dd if=/dev/zero of=File1 bs=1024 count=1000000 Warning: don't make bs too small or the process will be very slow.
I usually write a blog post about once a week. The latest post can be viewed here: Respect the Flag?: Find me a Maori flag and I will burn it. (posted 2025-05-31 at 18:45:40). I do podcasts too!. You can listen to my latest podcast, here: OJB's Podcast 2025-04-24 Go Winston!: If a politician want's to empower the majority view then I'm all for it..
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