i know its for brakes but just which side i have no clue they mess all under the car

 

That line goes to the rear brakes.

 

thanks for fast response.. So im assuming the other side directely behind it near firewall is for front. so what did i do wrong as i cut off the line on the proportion valvle facing right side engine on left side that valve in rear i assumed that was for front right brake line which i was wrong grrrrr what a mess i should look into moving closer to auto service stations. four lines one in front u tell me is for rear so line in rear should be for front brakes and the lines to the left?