Use Linux shred to securely delete/erase simple files including hard disks

Fig.01: Use shred to securely delete simple files including hard disks

Fig.01: Use shred to securely delete simple files including hard disks

The only way to make recovering of your sensitive data nearly impossible is to overwrite (“wipe” or “shred”) the data with several defined patterns. The syntax is:
shred -v /dev/hda
shred -v /dev/sda
shred -v /dev/da0

Sample outputs:

shred: /dev/sda: pass 1/6 (random)...
shred: /dev/sda: pass 1/6 (random)...359MiB/373GiB 0%
shred: /dev/sda: pass 1/6 (random)...726MiB/373GiB 0%
shred: /dev/sda: pass 1/6 (random)...1.0GiB/373GiB 0%
shred: /dev/sda: pass 1/6 (random)...1.4GiB/373GiB 0%
shred: /dev/sda: pass 1/6 (random)...1.7GiB/373GiB 0%
shred: /dev/sda: pass 1/6 (random)...2.1GiB/373GiB 0%
shred: /dev/sda: pass 1/6 (random)...2.4GiB/373GiB 0%
shred: /dev/sda: pass 1/6 (random)...2.8GiB/373GiB 0%
shred: /dev/sda: pass 1/6 (random)...3.1GiB/373GiB 0%
shred: /dev/sda: pass 1/6 (random)...3.4GiB/373GiB 0%
shred: /dev/sda: pass 1/6 (random)...3.8GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...4.1GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...4.5GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...4.9GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...5.2GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...5.5GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...5.9GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...6.3GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...6.6GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...7.0GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...7.3GiB/373GiB 1%
shred: /dev/sda: pass 1/6 (random)...7.7GiB/373GiB 2%
shred: /dev/sda: pass 1/6 (random)...8.0GiB/373GiB 2%
shred: /dev/sda: pass 1/6 (random)...8.4GiB/373GiB 2%
shred: /dev/sda: pass 1/6 (random)...8.7GiB/373GiB 2%
shred: /dev/sda: pass 1/6 (random)...9.1GiB/373GiB 2%
shred: /dev/sda: pass 1/6 (random)...9.4GiB/373GiB 2%
shred: /dev/sda: pass 1/6 (random)...9.8GiB/373GiB 2%
shred: /dev/sda: pass 1/6 (random)...10GiB/373GiB 2%
shred: /dev/sda: pass 1/6 (random)...11GiB/373GiB 2%
shred: /dev/sda: pass 1/6 (random)...12GiB/373GiB 3%
shred: /dev/sda: pass 1/6 (random)...13GiB/373GiB 3%
shred: /dev/sda: pass 1/6 (random)...14GiB/373GiB 3%
shred: /dev/sda: pass 1/6 (random)...15GiB/373GiB 4%
shred: /dev/sda: pass 1/6 (random)...16GiB/373GiB 4%
shred: /dev/sda: pass 1/6 (random)...17GiB/373GiB 4%
shred: /dev/sda: pass 1/6 (random)...18GiB/373GiB 4%
shred: /dev/sda: pass 1/6 (random)...19GiB/373GiB 5%
shred: /dev/sda: pass 1/6 (random)...20GiB/373GiB 5%
shred: /dev/sda: pass 1/6 (random)...21GiB/373GiB 5%
shred: /dev/sda: pass 1/6 (random)...22GiB/373GiB 5%
shred: /dev/sda: pass 1/6 (random)...23GiB/373GiB 6%
shred: /dev/sda: pass 1/6 (random)...24GiB/373GiB 6%

It may take hours to complete erase the disk.

Examples and usage: How do I permanently erase hard disk?