Modify UTC date modeline to be shorter

init.lisp

@@ -34,7 +34,7 @@
   (declare (ignore ml))
   (string-right-trim '(#\Newline)
                      (run-shell-command
-                      "TZ='UTC' date''" t)))
+                      "date -u --rfc-3339=seconds | cut -d '+' -f 1" t)))
 
 (add-screen-mode-line-formatter #\U #'utc-time)