 Shred has an option to overwrite only the file itself, as well as an option to delete the file after it has completed operation.A limitation of shred when invoked on ordinary files is that it only overwrites the data in place without overwriting other copies of the file.Copies can manifest themselves in a variety of ways, such as through manual and automatic backups, file system snapshots, copy-on-write filesystems, wear leveling on flash drives, caching such as NFS caching, and journaling.