HOWTO easily hex edit large files in Linux

Have you ever tried to open a 80GB file in a hex editor. The fancy GUI editors try to load the whole file…needless to say, that is rather painful. There are two great tools I use in Linux.

xxd

xxd is dumps a file in hex to the screen. If you pipe it through less, you can quickly view a file. You can also the -a option to auto skip so it’s a great way to verify that a drive has been wiped (i.e. xxd -a /dev/sdd).

hexedit

Hexedit is a Ncurses based hex editor. It is easy to navigate (arrow keys), you can tab between the hex and ASCII output and switch into edit more to change and then write a file. This is great when, for instance, working with a dd image from Apple’s iPhone. The file system is HSF/X (fifth generation HFS) and you need to change the identifier at 0×0400 from HX to H+ for most tools to recognize the file file system.

I’m sure there are other great editors people use…please let me know and I’ll try it out and post here.