Computer Tips - Can a shell script do rot13 "encryption" ?

Date: 2011apr5 OS: Linux Q. Can a shell script do rot13 "encryption" ? A. Yes, like this:
#!/bin/sh exec tr 'a-zA-Z' 'n-za-mN-ZA-M'
Save it as /usr/local/bin/rot13 and do:
chmod a+x /usr/local/bin/rot13
Use it like this:
echo hello | rot13