Gammu is a command line program to send sms and manage the phone.

Gammu is a command line program that provides an abstraction capability to access and control the phone; although the level of support varies from one phone to another, it allows the handling of calls, contacts and the handling of SMS (sending SMS with the help of the Gammu daemon).

In short, Gammu allows you to automate the handling of telephones, among others, the sending and receiving of large amounts of messages; In the following link you can see the phones supported by Gammu: Gammu phone database.