cd_hook: do not invoke actions if in a bash subshell

bash_aliases

@@ -93,11 +93,14 @@ function cd_hook_show_git_status()
 }
 function cd_hook()
 {
+    if [[ $BASH_SUBSHELL == 0 ]]; then
+        # do not invoke these CD hooks in subshells
         if [[ "${cd_hook_last_wd}" != "${PWD}" ]]; then
             cd_hook_cat_todo
             cd_hook_show_git_status
             cd_hook_last_wd="${PWD}"
         fi
+    fi
 }
 # Invoke cd_hook when we're loaded
 cd_hook