gistfile1.txt

" comment an entire visual block at once
" highlight the area however you want (V, CTRL+V) then 
" ,c will comment the block
" ,u will uncomment the block
let b:comment_leader = '# '
au FileType haskell,vhdl,ada            let b:comment_leader = '-- '
au FileType vim                         let b:comment_leader = '" '
au FileType c,cpp,java,php,js           let b:comment_leader = '// '
au FileType sh,make,perl,ruby,python    let b:comment_leader = '# '
au FileType tex                         let b:comment_leader = '% '
noremap <silent> ,c :<C-B>sil <C-E>s/^/<C-R>=escape(b:comment_leader,'\/')<CR>/<CR>:noh<CR>
noremap <silent> ,u :<C-B>sil <C-E>s/^\V<C-R>=escape(b:comment_leader,'\/')<CR>//e<CR>:noh<CR>