Good tip for showing hex from within vi. Thanks YorkshireKev!
http://www.kevssite.com/2009/04/21/using-vi-as-a-hex-editor/
In case that goes away, just stream with xxd to display hex:
:%!xxd
Off again with:
:%!xxd -r
If you are more of a GUI fan, and want to install one without many dependencies, give Jeex a try:
P.S. Thanks tuxdiary.com. Great site for tips and tools.
https://tuxdiary.com/2016/08/07/jeex/#more-27737