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

You also get nice syntax highlighting (if you have syntax highlighting correctly setup in general).

Change that “*.bin” to whatever comma-separated list of extension(s) you find yourself wanting to edit.

This tip actually comes from :help hex-editing
http://vimdoc.sourceforge.net/htmldoc/tips.html#hex-editing

Cheers, Janos
http://www.bashoneliners.com/

Otherwise vi will append a newline (0x0a) at the end of the file.

This is only an issue when creating a new binary file. When you open an existing binary file vi automatically sets these flags for you.

Janos
http://www.bashoneliners.com/

Thanks for not suppressing (entirely) the comment. With more research I found that vi’s “hexadecimal mode” is a sort of urban legend, and, sadly, doesn’t only belong to your blog. It would be harsh to ask EVERY blog editor to correct their version (which on the top of that are all slightly different). So, I give up. The world gonna stay the stinking heap of lies it is.

On the other hand your edits made me smile (I’m not being sarcastic by the way), and I don’t think my original text was that insulting. But I do agree, it wasn’t that nice either and it’s your blog.

So, if you ever read that, I don’t care if you remove this comment, AS LONG AS YOU CLEAR THINGS UP IN YOUR POST.

[more snipping], here is a more correct version of it :

” Sometimes I find it useful to switch to hex mode when editing a file in vi. vi doesn’t have such a feature, but it has the capability of using an external program as a ‘filter’ (meaning that the input (stdin) of the program is taken from vi buffer, which is later replaced by its output (stdout)). xxd is the binary used to transform one’s binary into hexadecimal and vice versa. The vi command for using it as a filter is not very obvious so thought I’d share…

So, open a file in vi as usual, hit escape and type:
:%!xxd
to switch into hex mode

And when your done hit escape again and type:
:%!xxd -r
to exit from hex mode.

As you can easily figure it out, ‘:[address-range] ! external-command-name’ is vi’s command for filtering. % as an address-range means : everything in the buffer. See http://www.softpanorama.org/Editors/Vimorama/vim_piping.shtml for further information.”