Hed: The Hexadecimal Editor
Hed
is a free hexadecimal editor
for POSIX systems
designed to efficiently handle
infinitely large files
in conjunction with operations like inserting
in the middle of the file.
Hed is maintained by Petr Baudis
and distributed as free software under GPLv2.
Features
Very fast on very large files (keeps only necessary portion of the file in memory)
Fast inserting anywhere in the file
Fast saving of intermediate changes
vim-like controls (and exmode)
Powerful expressions concept for flexible searching and transformation operations on the file or a selected region
Development
Hed is developed using Git
development version control system. You can get details on
how to grab the latest version at
its gitweb 
