Edit a file in hex using Vim

From AdminWiki

• To edit a binary file, start vim like so (:w and such will work like a charm then):

vim -b <file>

• To edit a buffer in hex, use xxd this way:

:%!xxd

• To return your buffer to normal (and make it save-able):

:%!xxd -r

• To use xxd only for a part of your buffer, you can use your normal buffer selection methods, like visual - just omit the %.