diff --git a/tools/check_for_upgrade.sh b/tools/check_for_upgrade.sh
index e1e4eb99f..1a6ddf2c3 100644
--- a/tools/check_for_upgrade.sh
+++ b/tools/check_for_upgrade.sh
@@ -19,12 +19,15 @@ then
   epoch_diff=$(($(_current_epoch) - $LAST_EPOCH))
   if [ $epoch_diff -gt 6 ]
   then
+    if [ -z "$ZSH" ]
+      ZSH=$HOME/.oh-my-zsh
+    echo $SHELL
     echo "[Oh My Zsh] Would you like to check for updates?"
     echo "Type Y to update oh-my-zsh: \c"
     read line
     if [ "$line" = Y ] || [ "$line" = y ]
     then
-      /bin/sh $ZSH/tools/upgrade.sh
+      $SHELL "$ZSH/tools/upgrade.sh"
       # update the zsh file
       _update_zsh_update
     fi