function! Redir(cmd, rng, start, end)
  for win in range(1, winnr('$'))
    if getwinvar(win, 'scratch')
      execute win . 'windo close'
    endif
  endfor
  if a:cmd =~ '^!'
    let cmd = a:cmd =~' %'
      \ ? matchstr(substitute(a:cmd, ' %', ' ' . expand('%:p'), ''), '^!\zs.*')
      \ : matchstr(a:cmd, '^!\zs.*')
    if a:rng == 0
      let output = systemlist(cmd)
    else
      let joined_lines = join(getline(a:start, a:end), '\n')
      let cleaned_lines = substitute(shellescape(joined_lines), "'\\\\''", "\\\\'", 'g')
      let output = systemlist(cmd . " <<< $" . cleaned_lines)
    endif
  else
    redir => output
    execute a:cmd
    redir END
    let output = split(output, "\n")
  endif
  vnew
  let w:scratch = 1
  setlocal buftype=nofile bufhidden=wipe nobuflisted noswapfile
  call setline(1, output)
endfunction

command! -nargs=1 -complete=command -bar -range Redir silent call Redir(<q-args>, <range>, <line1>, <line2>)