Options for secure file removal in the OS X Terminal
While deleting files in OS X simply involves moving them to the trash and emptying it, this routine does not remove the data of these items, but instead only clears the directory entry for them. The content of the items is kept on disk with the system having no way to access it; as a result, there is potential for the content to be scanned and recovered by data recovery tools.
To prevent this from happening, you can use secure-erase features in OS X, one of which is to securely delete the files in the Finder by choosing this option … Read more