Hexyl: A command-line hex viewer
Slightly off tangent: One tool I have used to dump data (and more) is cxmon. A very nice monitor if one grew up using monitor cartridges on C64, Amiga etc:<p><a href="http://cxmon.cebix.net/" rel="nofollow">http://cxmon.cebix.net/</a><p><a href="https://github.com/cebix/macemu/tree/master/cxmon" rel="nofollow">https://github.com/cebix/macemu/tree/master/cxmon</a>