Interesting timing… following on the heels of my rather long entry regarding using gpg to encrypt a file and shred to securely erase the original, Linux.com ‘s CLI Magic column has an article detailing securely deleting files with shred
Deleting a file with the rm command merely adds a file’s data blocks back to the system’s free list. A file can be restored easily if its “freed” blocks have not been used again. shred repeatedly overwrites a file’s space on the hard disk with random data, so even if a data recovery tool finds your file, it will be unreadable. By default, shred does not delete a file, but you can use the -u or –remove switch to delete it.
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By default shred overwrites a file 25 times with random data. You can increase or decrease the number of repetitions using the -n switch. For instance, shred -n 5 -v visit_sites.txt would overwrite the file visit_sites.txt five times and show you the the progress (-v).
