Array strings/Loops problem

what happening your code is running for each cheat code inside you list, try debugging you msgInfos and both of them came up regardless...the problem was that even after you found a match or an error, your looping code would continue to run causing you problems, Unity reconied all your strings all along, its was just made hard due to a tiny logical mistake

 #pragma strict
 
 
 var cheatField : String = "Cheat code";
 var cheatCodes : String[];
 var msgInfos : String;
 
 
 function OnGUI() {
     if (GUI.Button(Rect(Screen.width - Screen.width, Screen.height - 60, 250, 20), "Try debugging")) {
  
 
         var match = false;
         for (var i : int = 0; i < cheatCodes.Length; i++) {
  
             //for (var code : String in cheatCodes) {
  
                if (cheatField.ToUpper() == cheatCodes[i].ToUpper()) {
  
                    match = true;
                   msgInfos = "Code recognized";
                   Debug.Log(msgInfos);
                     }
                 }
 
     if (match == false) {
  
         msgInfos = "Error : unknown code !";
         Debug.Log(msgInfos);
     }
     match = false;
  
 
     }
 }

I have edited your code, my Unity Script is poorly formatted i apologies. to fix your issue, i moved your Error Message outside of the loop then i changed the condition to check for a bool called watches was false, i then set it to true whenever a reconised string was put through and done!

Debug.Log is a very useful function and lets you know everything that goes on if you use it right

Hope it helps