This is a hexadecimal editor. Here's how it works:

1. You type hexedit blah.bin
2. It dumps out the contents of blah.bin in hex to a temporary text file.
3. Every time you save that file, it picks up the change and writes the alteration back to blah.bin.
4. When the editor exits, it writes the change back to blah.bin.

Each line in the editor is something like this:

# offset: data                                     # ASCII value.
00000000: 5468 6973 2069 7320 6120 6865 7861 6465  # This.is.a.hexade
00000010: 6369 6d61 6c20 6564 6974 6f72 2e20 2048  # cimal.editor...H
00000020: 6572 6527 7320 686f 7720 6974 2077 6f72  # ere's.how.it.wor
00000030: 6b73 3a0a 0a31 2e20 596f 7520 7479 7065  # ks:..1..You.type

The annotations and whitespace are just for your benefit, and are ignored by the program. Everything before the first :, or after the first # is removed. Whitespace is stripped. If there are any invalid hex characters after this transformation, or if the result is an odd number of hex digits, then an error is thrown.

You need to set a blocking editor as your EDITOR environment variable. vim works, or if you're on a Mac and use TextMate, you can use mate_wait. Anything that works for commit messages should be fine.

Installing

npm install hexedit -g

There is no module to require(). It's strictly a command-line utility.

Options

Hexedit takes all the same options that hexy takes, and they do the same things.

Usage: hexedit [options] <file>
Options are identical to hexy's:
 --width     [(16)]              how many bytes per line
 --numbering [(hex_bytes)|none]  prefix current byte count
 --format    [(fours)|twos|none] how many nibbles per group
 --caps      [(lower)|upper]     case of hex chars
 --annotate  [(ascii)|none]      provide ascii annotation
 --prefix    [("")|<prefix>]     printed in front of each line
 --indent    [(0)|<num>]         number of spaces to indent output
 --help|-h                       display this message