Secure delete with secure-delete

Trick copyright: The Book of Secret Knowledge <https://github.com/trimstray/the-book-of-secret-knowledge>

srm -vz /tmp/file
sfill -vz /local
sdmem -v
swapoff /dev/sda5 && sswap -vz /dev/sda5

click the source code to copy install dd on any operating system with command-not-found.com