Help with shell scripting

I'm taking a Unix class and we're supposed to write two scripts
The first one looks up every .c and .cc file in the current directory for the strings "printf" and "fprintf". If either string is found, the script adds "#include <stdio.h>" to the beginning of the file unless it's already been included.

The second compares two directories dir1 and dir2 (supplied as arguments) and copies and overwrites to dir1 from dir2 every file that is not present in dir1 or newer than its namesake in dir1.

I'm trying to write the first one right now, and I think I'm close, but I'm getting an error. I'm really new to shell scripting and *nix in general.

http://pastebin.com/RHmTdjYw

>>13
I took one look at that and felt nauseous. (I only skimmed it, but don't you have one too many greps in there?) Then I banged out a Perl 6 version which was immediately unreadable to me. No other language has tricked me into relying on nested closures so much (it had the form: for grep {...}, (for grep {...}, (for() {...}) {...} ) {...} roughly, and read each file up to 3 times.)