So up until now my use of eDirectory has been pretty vanilla, so while this task may seem easy to some (most (all)) it appears quite daunting to me.

I need to change the "Telephone" attribute for all users. Instead of what it was, which was the building line, it needs to be their direct extension. Now I assume there's a bulk method of performing this change, and I've Googled the subject, but it's a problem with many different solutions it would seem. My best guess at the moment is that I will need to export the directory into LDIF and then merge the LDIF file with a phone directory list somehow, then import. That sounds really painful. Like, just go in and manually add the correct extension to every user painful. At the very least I have no idea how to do it.

What's the best method to make this happen? I'm sure I'm not the first.