Hi Maddogpro,
Have you been out in the car since undoing the rear brake line?
If you havn't its pretty easy - there is the old school way of doing it.
Make sure that you have plenty of brake fluid in the resevoir.
Make sure the rear brake line that you disconnected is tight.
Get your lass or a mate to sit in the drivers seat and pump up the brake pedal until it is hard.
If you get a spanner on the bleed nipple and get them to press and hold the pedal down, then undo the nipple until fluid comes out, then quickly tighten it. Get your assistant to release the pedal and then hold it down again as you undo it again until the fluid comes out then tighten again.
Do this a couple of times and that should be okay.
Recheck brake fluid level.
If you remove anymore than one side of the system you will need to go through the full process. Which is a lot more involved.
If you do not have an assistant get an old bit of clean hose on the end of the nipple and submerge the end of it in a jar with a few inches of brake fluid in, undo the nipple & pump the pedal a few times then quickly retighten the nipple and all will be okay.
Best of luck!