I would like to add multiple User Custom Actions on several sites using PowerShell. The custom actions must be added in the top ribbon that is visible when selecting a list item. Is that even possible? When looking at SPList userCustomActions property, it is readonly, according to MSDN . Am I taking the wrong path? The property is readonly but the custom actions are there, so they must have been added.
So far I've been there.
$w = get-spweb $webUrl;
$l = $w.lists[$listTitle];
$userCustomActions = $l.userCustomActions;
Of course, custom Actions can be added via JS, C# + feature, SharePoint Designer. But I can't use those methods, So I'm only interested in PowerShell procedures.