Scalpel is a fast file carver that reads a database of header and footer
definitions and extracts matching files or data fragments from a set of
image files or raw device files. Scalpel is filesystem-independent and will
carve files from FATx, NTFS, ext2/3, HFS+, or raw partitions. It is useful
for both digital forensics investigation and file recovery.

To use it, you MUST have a conf file that defines the file types you want
to recover.  Use the example scalpel.conf file from /usr/doc/scalpel

See the man page for details.
