diff --git a/misc.vim b/misc.vim
new file mode 100644
index 0000000..f3c48fe
--- /dev/null
+++ b/misc.vim
@@ -0,0 +1,21 @@
+func s:mdxUpdateDate()
+  " guard ---
+  if getline(1) != "---" | return | endif
+  " find end ---
+  let lineEnd = search('\v%>1l^---$', 'n')
+  if lineEnd == 0 | return | endif
+  " prepare
+  let now = strftime('%Y/%m/%d(%a) %H:%M:%S')
+  let patpfx = '\v%>1l%<'.lineEnd.'l'
+  " createdAt
+  let line = search(patpfx.'^createdAt:\s*$', 'n')
+  if line > 0 | call setline(line, 'createdAt: '.now) | endif
+  " createdAt
+  let line = search(patpfx.'^updatedAt:', 'n')
+  if line > 0 | call setline(line, 'updatedAt: '.now) | endif
+endfunc
+
+augroup sup39_vimrc_misc
+  au!
+  au BufWritePre *.mdx call <SID>mdxUpdateDate()
+augroup END