You have not provided too many details, like who your phone provider is, please provide as much info as possible in future (without giving out personal details) so that we can help.
Assuming that you have att mobile and your phone number would be 1234567890, your mobile email is possibly
1234567890@mobil.att.net (you have to figure this yourself by calling your mobile provider).
Then, in your home directory create a .forward file (the dot is important). Again assuming that you are running sendmail and it allows you to forward email.
In the .forward file put
1234567890@mobil.att.net, all on one line and give it a try. Ideally you should create a seperate email account and forward that to your cell phone otherwise you may get huge emails on your phone which may be unreadable.
Is this what you are asking ? I am not sure why you would need a unix script ?