Is there a way to make sure that a deleted file can not be recovered?
As you know, deleting a file by pressing shift-del or using trash doesn't mean that file is gone forever. It resides somewhere in the computer.
In day to day life, law enforcement or thieves use recovery programs to reveal our private data or something else.
They can recover all data that resides on hard disk, in RAM, and even USB.
To protect us from these people, what should one do? Which program should one use?
Note: I don't want an answer like first use a recovery program then erase that file with shred. With just one program, I want to erase all unused/deleted files on my computer.