Blat - -to <recipient>
Blat - -cc <recipient>
Blat - -bcc <recipient>

This is a comma separated list of the the eMail addresses you are sending to.

The allowed formats are
                          blat@eMail.tld The basic way - just the eMail address.
"fName lName <blat@eMail.tld>" This is how you tell the MUA that is reading the message to display a 'Vanity Name' instead of the the eMail address.
"fName lName <blat@eMail.tld> Hey fName" Here is a cool one, you can add a customized salutation line to the begining of the message like this!
"fName lName <blat@eMail.tld> Hey fName\," This is how you would put a comma after the salutation.
blat1@eMail.tld,blat2@eMail.tld,blat3@eMail.tld This is how you use multiple addresses.

To: is typically the orriginal addressee
Cc: stands for carbon copy, and is additional recipients
Bcc: stands for Blind carbon copy

Bcc: allows you to send to a list of addresses without letting the recipients know who all it was sent to.

-t|-c|-b may also be used.