add Vimdiff function

functions/Vimdiff.vim

@@ -0,0 +1,28 @@
+" see: https://brookhong.github.io/2016/09/03/view-diff-file-side-by-side-in-vim.html
+
+function! Vimdiff()
+    let lines = getline(0, '$')
+    let la = []
+    let lb = []
+    for line in lines
+        if line[0] == '-'
+            call add(la, line[1:])
+        elseif line[0] == '+'
+            call add(lb, line[1:])
+        else
+            call add(la, line)
+            call add(lb, line)
+        endif
+    endfor
+    tabnew
+    set bt=nofile
+    vertical new
+    set bt=nofile
+    call append(0, la)
+    diffthis
+    exe "normal \<C-W>l"
+    call append(0, lb)
+    diffthis
+endfunction
+autocmd FileType diff       nnoremap <silent> <leader>vd :call Vimdiff()<CR>
+

vimrcs/basic.vim

@@ -63,7 +63,7 @@ nmap <leader>w :w!<cr>
 
 " :W sudo saves the file 
 " (useful for handling the permission-denied error)
-command W w !sudo tee % > /dev/null
+command! W w !sudo tee % > /dev/null
 
 
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