Software to insert note in all files for GNU

Question

I've developed a software and want to submit it in GNU.
But for that i need to insert GNU notice in all the files.
Is there any free software to do this job [inserting a common note to all file ] ?

Answer 1

Yes. It's called cat.

cat notice.txt origfile.txt > newfile.txt && mv newfile.txt origfile.txt

Answer 2

In bash:

for i in `find . -type f` ; do
  cat notice.txt $i > $i.new && mv $i.new $i
done

You probably want to back up your tree before you run this.