Capture output from a vim command (like :version or :messages) into a split scratch buffer.

Page.vim

"Examples:
":Page version
":Page messages
":Page ls
"It also works with the :!cmd command and Ex special characters like % (cmdline-special)
":Page !wc %
"Capture and return the long output of a verbose command.
function! s:Redir(cmd)
   let output = ""
   redir =>> output
   silent exe a:cmd
   redir END
   return output
endfunction

"A command to open a scratch buffer.
function! s:Scratch()
   split Scratch
   setlocal buftype=nofile
   setlocal bufhidden=wipe
   setlocal noswapfile
   setlocal nobuflisted
   return bufnr("%")
endfunction

"Put the output of acommand into a scratch buffer.
function! s:Page(command)
   let output = s:Redir(a:command)
   call s:Scratch()
   normal gg
   call append(1, split(output, "\n"))
endfunction

command! -nargs=+ -complete=command Page :call <SID>Page(<q-args>)