Changing multiple children's tags

How do I go about scripting a way, of changing all children objects tag's. any help would be appreciated this may take a lot of time manually :-)

Put this in a script and attach it to the parent. The tags will change upon selection:

function OnDrawGizmosSelected () 
{
   for (var  child : Transform in transform) 
   {
      child.gameObject.tag = "newName";
   }
}

Make sure the tag you try to change it to exists in the tag manager first!

This should be done like in Cinema 4d. In here you can change any parameters for all selected object in one time!! DIRECTLY IN THE EDITOR WITHOUT WRITING ANY SCRIPTS..But who knows, that feature is implemented in Unity3D 3.0?

(Self-Disclosure: This answer is from a producer of a paid item in the Unity Asset Store.)

Ran into the same issue, especially with deep hierarchies to change specific tags and/or layers but not others. Or for that matter, just to find out which tags and layers were in a given scene or hierarchy.

There are several good answers, including the one above and also in the Unity Script Reference under EditorGUI.LayerField. However, a more comprehensive tool was needed for a project and so this was developed: Find Replace Tags Layers | Tools | Unity Asset Store. (Apologies for the off-center screenshot at this link: it’s either this or the right side gets cut off in the Asset Store.)