Vim syntax coloring: How do I highlight long lines only?

Question

I would like vim to color "long" lines for me. Using 80 columns as an example, I would like to highlight lines that exceed that length. Here is roughly what I think the .vimrc file should contain, although it (1) doesn't work, and (2) uses Perl's regex syntax to illustrate my point, because I don't know Vim's well enough:

...
highlight Excess ctermbg=0
au Syntax * syn match Excess /.{80,}$/
...

This (in my mind at least) should mark lines that exceed 80 columns. What I would ideally like is the ability to color only the part of the line that exceeds 80 columns, so if a line is 85 columns, then the 81st through the 85th columns would be highlighted.

I'm sure Vim can do this, just not with me at the helm.

Answer 1

I needed the autocomand to work for me:

augroup vimrc_autocmds
  autocmd BufEnter * highlight OverLength ctermbg=darkgrey guibg=#111111
  autocmd BufEnter * match OverLength /\%75v.*/
augroup END

Also like the idea of using 75 if you are aiming at 80 columns in average.

Taken from:

http://blog.ezyang.com/2010/03/vim-textwidth/

Possible reason why it fails without BufEnter: highlight + match can only be used once. Multiple usage means that old ones are overridden. How to add multiple highlights

Answer 2

I have this in my vimrc.
I found it here: Vim 80 column layout concerns

highlight OverLength ctermbg=darkred ctermfg=white guibg=#FFD9D9
match OverLength /\%81v.*/

You might want to adjust the colors to your preferences.