Disable hardware back button in Ionic application?

Finally found the answer on this Ionic Forum thread:

$ionicPlatform.registerBackButtonAction(function () {
  if (condition) {
    navigator.app.exitApp();
  } else {
    handle back action!
  }
}, 100);

$ionicPlatform.registerBackButtonAction allows to completly overwrite back button behavior. First param is a callback function and the secondone a priority (only the callback with the highest priority gets executed).

Its simple trick prevent go back to single page:

  `.controller('DashCtrl', function($scope,$ionicHistory) {
                $ionicHistory.clearCache();
                $ionicHistory.clearHistory();

       })`

$ionicPlatform.registerBackButtonAction(function (event) {
    event.preventDefault();
}, 100);

this will prevent back button functionality.

To expand upon David D's answer I have included the go back implementation.

Put this in your applications .run function:

$ionicPlatform.registerBackButtonAction(function (event) {
  if ($ionicHistory.currentStateName() === 'someStateName'){
    event.preventDefault();
  } else {
    $ionicHistory.goBack();
  }
}, 100);

This will not work in controllers, it is application wide.