Is this for a high-security envrionment? I hope not. Most shredding will not work for filesystems that do not (for various reasons) immediately wrote over a deleted file.

FileBuzz - Find Software Fast has some simple shredder utilities that will keep an uninformed manager happy but will probably never pass a security audit.

You can google for 'file shredder' - Linux has one called shred. It is opensource, so you can compile it if you have gcc.