Hey all! Long time no see....

OK I'm trying to edit a hex file by hand. If I make a change and save then run a diff on the original and the modified version, of course I see a difference. The problem is when I try and return the file to its original state diff still complains. It also looks like the file grew. I need to be able to return it to its original state.


I open the file up using the following command:

vi test.bin

Fire up xxd:

:%!xxd

I then edit a couple bytes until I'm happy then revert it with this command:

:%!xxd -r

Then save and quit

:wq

I can't return the file back to its original state to make diff stop complaining. Any suggestion?

Found it!

For those of you that ever have this problem, here is the solution. Apparenly xxd -r does interesting things when inside vi and not in binary mode. To avoid this, put the following in your .vimrc, and open the file in binary mode: vim -b

" vim -b : edit binary using xxd-format!
augroup Binary
au!
au BufReadPre *.bin let &bin=1
au BufReadPost *.bin if &bin | %!xxd
au BufReadPost *.bin set ft=xxd | endif
au BufWritePre *.bin if &bin | %!xxd -r
au BufWritePre *.bin endif
au BufWritePost *.bin if &bin | %!xxd
au BufWritePost *.bin set nomod | endif
augroup END

Using this, Vim can be used as a pretty cool hex editor. Happy editing!!!