I have a sidebar that includes an excerpt of a specific page.
When viewing the index.php, the excerpt appears in the sidebar properly. When viewing a single.php post, the sidebar displays the full content of the specific page, instead of an excerpt.
I want it to always and only show an excerpt of a specific page in the sidebar. I need it to be unrelated to whether or not you're on index.php, single.php or anything like that. How can this be done?