Compute, compare, or audit multiple message digests

-k     Load  a file of known hashes.  This flag is required when using any of the matching or audit modes
       (i.e. -m, -x, -M, -X, or -a) This flag may be used more than once to add multiple  sets  of  known
       hashes.

       Loading  sets with different hash algorithms can sometimes generate spurrious hash collisions. For
       example, let's say we have two hash sets, A and B, which have some overlapping files. For example,
       the  file  /usr/bin/bad  is  in  both  sets.  In A we've recorded the MD5 and SHA-256.  In B we've
       recorded the MD5, SHA-1, and SHA-256. Because these two records are different, they will  both  be
       loaded. When the program computes all three hashes and compares them to the set of knowns, we will
       get an exact match from the record in B and a collision from the record in A.

-r     Enables recursive mode. All subdirectories are traversed. Please note that recursive  mode  cannot
       be  used  to  examine  all files of a given file extension. For example, calling hashdeep -r *.txt
       will examine all files in directories that end in .txt.

-l     Enables relative file paths. Instead of printing the absolute path for  each  file,  displays  the
       relative file path as indicated on the command line. This flag may not be used in conjunction with
       the -b flag.

-e     Displays a progress indicator and estimate of time remaining for each file being  processed.  Time
       estimates  for  files larger than 4GB are not available on Windows. This mode may not be used with
       th -p mode.

-o <bcpflsd>
       Enables  expert mode. Allows the user specify which (and only which) types of files are processed.
       Directory processing is still controlled with the -r flag. The expert mode options allowed are:
       f - Regular files
       b - Block Devices
       c - Character Devices
       p - Named Pipes
       l - Symbolic Links
       s - Sockets
       d - Solaris Doors

-a     Audit mode. Each input file is compared against the set of knowns.  An audit is said  to  pass  if
       each  input  file is matched against exactly one file in set of knowns. Any collisions, new files,
       or missing files will make the audit fail. Using this flag alone produces a message, either "Audit
       passed" or "Audit Failed". Use the verbose modes, -v, for more details. Using -v prints the number
       of files in each category. Using -v a second time prints any discrepancies. Using -v a third  time
       prints the results for every file examined and every known file.
       Due to limitations in the program, any filenames with Unicode characters will appear to have moved
       during an audit. See the section "UNICODE SUPPORT" below.

-v     Enables verbose mode. Use again to make  the  program  more  verbose.   This  mostly  changes  the
       behvaior of the audit mode, -a.