$. What it does?
This tool walks down through the source directory tree.
Within each directory node, it reads the files.
By the file extension, you can specify which kind of the files to be read.
While iterating those files, it inserts the comment lines for the copyright notice into each of them.
Finally, the new files are written to the corresponding directory node under the destination directory tree.
$. Default templates
As default, I wrote the templates of the copryright notice...