Linux/Hex Editor

DHEX
apt: apt-get install dhex

source: wget http://www.dettus.net/dhex/dhex_latest.tar.gz tar -zvxf dhex_latest.tar.gz cd dhex_* # cd dhex_0.68 make sudo make install

wget http://www.dettus.net/dhex/dhex_0.68.tar.gz tar -zvxf dhex_0.68.tar.gz cd dhex_0.68 make sudo make install

site: http://www.dettus.net/dhex/

ref:

VIM
To view in hex: :%!xxd

You can try converting back to binary, but may add extra new lines: :%!xxd -r

Bless Hex Editor
apt install bless

Bless Hex Editor is a is a binary (hex) editor and currently provides the following features:
 * Efficient editing of large data files and block devices.
 * Multilevel undo - redo operations.
 * Customizable data views.
 * Fast data rendering on screen.
 * Multiple tabs.
 * Fast find and replace operations.
 * A data conversion table.
 * Advanced copy/paste capabilities.
 * Highlighting of selection pattern matches in the file.
 * Plugin based architecture.
 * Export of data to text and html (others with plugins).
 * Bitwise operations on data.
 * A comprehensive user manual.

ref:

hexcurse
sudo apt-get install hexcurse

ref:

ht
sudo apt-get install ht

hte

ref:

xxd
xxd [file]