Remove everything before "http://..." in string

Question

I have a txt with line like these ones:

155The Last Goodnight - Stay Beautiful by CapitolMusic http://www.youtube.com/watch?v=H5c2iTcSlbE
156Sara Evans - A Real Fine Place To Start by saraevansVEVO http://www.youtube.com/watch?v=IrdCBkXB91I
157Simple Minds - See The Lights by SimpleMindsVEVO http://www.youtube.com/watch?v=MmKTMAak710

I want to remove everything before "http://..." in order to reach this result:

http://www.youtube.com/watch?v=H5c2iTcSlbE
http://www.youtube.com/watch?v=IrdCBkXB91I
http://www.youtube.com/watch?v=MmKTMAak710

Can you help me?

• Marco Panichi: I can't try anything reasonable, becouse I'm new to reg exp. I've tryed to use reg exp builder as gskinner, expresso and regexpbuddy. Simply I can't understand how to start. I've tried an 1 hour before posting here (I know there are lots of know-all ready to put -1)
• Wil: I get the frustration. Regex is not something that you can reference on a need to know basis, and a cheatsheet is of no use if you have never sat down and practised it, but many regex tutorials treat it as such/ assume too much. Waste of an hour!

Answer 1

.*(?=http://)

matches everything before the last http:// in a line.

• Tim Pietzcker: @user128806: Yes, just use .*? instead of .*.

Answer 2

In Java:

justHttp = justHttp.replaceFirst(".*(?=http://)", "");

For any other use just replace http:// with yourString.