vim sed match more than one newline and replace it with one newline

Question

I'm having some trouble with vim, gg=G doesn't remove extra newlines, I'm trying with

:%s/\(\n\)\n\+/\1/g

but it's not working in the whole file. Any help appreciated.

Answer 1

" Put the function bellow in your vimrc
" remove extra newlines keeping the cursor position and search registers
fun! DelBlank()
   let _s=@/
   let l = line(".")
   let c = col(".")
   :g/^\n\{2,}/d
   let @/=_s
   call cursor(l, c)
endfun
" the function can be called with "leader" d see :h <leader>
map <special> <leader>d :keepjumps call DelBlank()<cr>

Answer 2

This should work in vim...

:g/^\s*$/d