hexpeek does things differently than most hex editors. It is designed for efficient use with any file, even generic file descriptors. In particular, because hexpeek does not map files into memory or assume file offsets are 32 bits, it has no size-related glitches and works well with huge files. Both a prompt interface with command history and a scriptable command interface are available, making the tool more accessible than a typical curses tool.
hexpeek is a fully featured editor: you can quickly jump to and work with specific parts, repeatedly write or copy data with ease, insert and delete arbitrary data, and search for data in hexadecimal or bits. You can easily create or revert a hex dump. Surgically moving data from one file to another is supported as is showing the differences between two files. A nice variety of formatting options is available, and hexpeek interprets scalar input as hexadecimal by default — no need for ugly 0x prefixes.
Finally, hexpeek implements a multi-level backup mode with a live undo, which to the author's knowledge cannot be found in any comparable tool. hexpeek runs on any recent POSIX-like system (including Cygwin) and is open source under a permissive BSD 3-clause license. No need to worry about a proprietary or GPL license.
Current source release [version 1.0.20200804]
E-mail can be sent to email@example.com [pubkey]. There is also an announcements mailing list.
Consider hiring the author for your next project!