diff --git a/setup.sh b/setup.sh
index d7085ec..5faca2a 100755
--- a/setup.sh
+++ b/setup.sh
@@ -12,12 +12,13 @@ verify () {
     done
 }
 
+time="$(date +%y%m%d_%H%M%S)"
 # ---------------- zshrc start ----------------
 echo "setting up zsh"
 if [ -e ~/.zshrc ]
 then
-    echo "~/.zshrc exists, backup to ./zshrc_backup"
-    mv ~/.zshrc ./zshrc_backup
+    echo "~/.zshrc exists, backup to ./zshrc_backup-$time"
+    mv ~/.zshrc ./zshrc_backup-$time
 fi
 ln ./zshrc ~/.zshrc