Custom fields script

I’ve added a custom field named CheckThisOut. Now whenever I add a post, I always have something CheckThisOut for that post. The custom field is part of my template, so it is displayed beautifully on all posts.

Now, I have collected CheckThisOut ‘s for my previous posts, but it is a humongous task to manually edit all my previous posts for that and manually insert those! And I want to do that because considerable traffic is being generated by old posts.

So, could there be an automated way, where, say, I can insert CheckThisOut custom fields to my old entries? I was thinking may be a script which takes a post ID and CheckThisOut from a text file that I’ll create (each line contains a post ID space and the data for CheckThisOut.

But I’m no programmer! 🙁 Anyone who could help me with that? Many thanks in advance!