strip whitespace. put in .vimrc

gistfile1.txt

" Remove trailing whitespace upon save
function! <SID>StripTrailingWhitespaces()
    " Preparation: save last search, and cursor position.
    let _s=@/
    let l = line(".")
    let c = col(".")
    " Do the business:
    %s/\s\+$//e
    " Clean up: restore previous search history, and cursor position
    let @/=_s
    call cursor(l, c)
endfunction
autocmd BufWritePre *.rb,*.rake,*.coffee,*.slim :call <SID>StripTrailingWhitespaces()