vnoremap <C-r> "hy:%s/<C-r>h//gc<left><left><left>

" search for visually hightlighted text
vnoremap <c-f> y<ESC>/<c-r>"<CR>

%s//<your-replacement-string>

" Escape special characters in a string for exact matching.
" This is useful to copying strings from the file to the search tool
" Based on this - http://peterodding.com/code/vim/profile/autoload/xolox/escape.vim
function! EscapeString (string)
  let string=a:string
  " Escape regex characters
  let string = escape(string, '^$.*/~[]')
  " Escape the line endings
  let string = substitute(string, 'n', '\n', 'g')
  return string
endfunction

" Get the current visual block for search and replaces
" This function passed the visual block through a string escape function
" Based on this - https://stackoverflow.com/questions/676600/vim-replace-selected-text/677918#677918
function! GetVisual() range
  " Save the current register and clipboard
  let reg_save = getreg('"')
  let regtype_save = getregtype('"')
  let cb_save = &clipboard
  set clipboard&

  " Put the current visual selection in the " register
  normal! ""gvy
  let selection = getreg('"')

  " Put the saved registers and clipboards back
  call setreg('"', reg_save, regtype_save)
  let &clipboard = cb_save

  "Escape any special characters in the selection
  let escaped_selection = EscapeString(selection)

  return escaped_selection
endfunction

" Start the find and replace command across the entire file
vmap <leader>z <Esc>:%s/<c-r>=GetVisual()<cr>/

vnoremap <C-r> <Esc>:%s/<C-r>+//gc<left><left><left>

function! GetVisual() range
    let reg_save = getreg('"')
    let regtype_save = getregtype('"')
    let cb_save = &clipboard
    set clipboard&
    normal! ""gvy
    let selection = getreg('"')
    call setreg('"', reg_save, regtype_save)
    let &clipboard = cb_save
    return selection
endfunction

vmap <leader>z :%s/<c-r>=GetVisual()<cr>/

:'<,'>

:'<,'>s/red/green/g

:%s,%V_.*%V/,**&**,c

:%s!%V_.*%V/!=system("base64 -w 0",@")!c