There's a tool call [DHEX][1] which may do the job.

And there's another tool called [VBinDiff][2]

For a strictly command-line approach, try [JDIFF][3]


  [1]: http://www.dettus.net/dhex/
  [2]: http://www.cjmweb.net/vbindiff/
  [3]: http://jojodiff.sourceforge.net/