efficient hex editor
Tweak is an ncurses-based hex editor. Tweak uses a complex data structure based on B-trees, designed to make almost all editing operations extremely fast, even when they are working on huge amounts of data. Unlike most hex editors, it also has a fully functional insert mode, along with full cut, copy, and paste support.
Homepage: https://www.chiark.greenend.org.uk/~sgtatham/tweak/
Maintainer: Anthony J. Bentley <anthony@anjbe.name>