rubenroques

view.addFallbackConstraints(item: labelB, attribute: .Top, relatedBy: .Equal, fallbackArrayItems:[topImageView], attribute: .Bottom, multiplier: 1, constant: 20, startPriority:110)
view.addFallbackConstraints(item: labelC, attribute: .Top, relatedBy: .Equal, fallbackArrayItems:[labelA,topImageView], attribute: .Bottom, multiplier: 1, constant: 20, startPriority:105)
view.addFallbackConstraints(item: labelD, attribute: .Top, relatedBy: .Equal, fallbackArrayItems:[labelB,labelA,topImageView], attribute: .Bottom, multiplier: 1, constant: 20, startPriority:100)


extension UIView {

    func addFallbackConstraints(item view1: AnyObject, attribute attr1: NSLayoutAttribute, relatedBy relation: NSLayoutRelation, fallbackArrayItems: [AnyObject], attribute attr2: NSLayoutAttribute, multiplier: CGFloat = 1, constant c: CGFloat, startPriority: UILayoutPriority) -> UILayoutPriority {
        var priorityDecrementer = startPriority

rubenroques

//Install Macports.
//Install aircrack-ng:
sudo port install aircrack-ng
//Install the latest Xcode, with the Command Line Tools.
//Create the following symlink:
sudo ln -s /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport /usr/sbin/airport
//Figure out which channel you need to sniff:
sudo airport -s

sudo airport en1 sniff [CHANNEL]