This took me some time on google / msdn sdk to find out, I like to share it. It is supposed to programmatically change content to existing pages.
First make a console application, set it to .NET Framework 3.5 and the build properties to x64.
This is an example that can be used to get some information about pages in the root site.
If somebody has some improvements or suggestions to make it better, I’d like to hear it.
static void ProcesPageData(string pageName, string contentType, string pageData)
//Retreive all the pages
//Print the page titles
//Retreive a specific page
//If the page exists, go on
//Check the page out
//For the safety check for the correct contenttype
//Overwrite the existing data
//Update and check it in
//Publish and approve the page