Is there any solution Like SharePoint in Linux?

Question

We have three server SharePoint , Project Server and CRM and we want to change them and migrate to Linux solutions.

Now we have to change SharePoint by Linux solution ?

we want to have a solution for collaboration management and document management

Answer 1

Alfresco is one I heard about: http://www.unixmen.com/alfresco-an-opensource-alternative-of-microsoft-sharepoint/