         
         frequency = _frequency
     }
+
+    func format() -> String {
+        // We assume that 4 digits are enough to hold dimensions.
+        // 10K monitor users will just have to live with a bit of formatting misalignment.
+        return String(
+            format:"%4d x %4d @ %dx @ %dHz",
+            width,
+            height,
+            scale,
+            frequency
+        )
+    }
 }
 
 

        "   -h          get help\n",
        "   -l          list displays\n",
        "   -m 0        list all mode from a certain display\n",
        "   -s 0 800    set resolution of display 0 to 800*600\n",
        "   -s 0 800 2  set resolution of display 0 to 800*600@2x\n",
        ]).joined(separator:"")
    let help_display_list = "List all available displays by:\n    \(binary_name) -l"
    

        if let displayIDs = self.displayIDs {
            for i in 0..<self.displayCount {
                let di = DisplayInfo(displayIDs[i])
                print("Display \(i):  \(di.format())")
            }
        }
    }
