One excellent hex editor available for Linux is called Okteta. It’s free and available from the Ubuntu repository. To view byte-level information of a file, either open the file from the menu or drag and drop it onto the Okteta window.
Even though Okteta is written for KDE, it runs well in Gnome. The Okteta GUI will have a KDE interface.
The decoding table in the upper right-hand corner of the program shows various values for the selected byte, and the dropdown menu at the bottom easily changes the file view to hexadecimal, binary, octal, or decimal.
Okteta – useful and convenient.