SHRED: Securely Delete Your Data
The only command you need is the following:
[user@computer ~]$ shred -uzv -n 5
Let's review what this does:
-u : Removes the file after overwriting -> shred, by default, just overwrites the file
-z : Overwrite with all zeros -> shred, by default, fills the file with random data
-v : Verbose mode -> You can remove if wanted, I like to see the process being done
-n 5 : Do this 5 times -> shred does it only once by default, I want to do it 5 times to make extra sure that the data is deleted
I highly suggest putting this command as an alias in your .bashrc file.
alias securedel = "shred -uzv -n 5"
This is so you do not have to memorize the command everytime. Very useful.