https://www.developershome.com/sms/cmgrCommand2.asp

First, enter the command line "AT+CMGF=1" in a terminal program (for example, HyperTerminal in Microsoft Windows) to instruct the GSM/GPRS modem or mobile phone to operate in SMS text mode. This step is necessary because the default mode is SMS PDU mode. 
<code>
AT+CMGF=1

OK
</code>

Second, use the AT command +CPMS (command name in text: Preferred Message Storage) to select the message storage area to read SMS text messages from. For example, to instruct the GSM/GPRS modem or mobile phone to use the message storage area in the SIM card for the AT command +CMGR, enter the command line 'AT+CPMS="SM"' in the terminal program (//more details [[https://www.developershome.com/sms/cpmsCommand.asp|here]]//)
<code>
AT+CPMS="SM","SM"
+CPMS: 2,10,2,10,3,160

OK
</code>

Third, you can now use the +CMGR AT command to read a text message from the message storage area. Let's say you would like to read the text message at index 1
<code>
AT+CMGR=1
</code>

To send SMS
<code>
AT+CMGS="xxxxxx"
</code>

To store SMS without sending
<code>
AT+CMGW="xxxxx"
</code>

To send similar message to multiple recipient
<code>
** use the AT+CMGW to store the message and get message location number **
AT+CMSS=id,"xxxxxx"
</code>

To list all SMS
<code>
AT+CMGL="ALL"
AT+CMGL="REC READ"
AT+CMGL="REC UNREAD"
AT+CMGL="STO UNSENT"
</code>

Other Basic AT Commands
  * AT
  * ATE   - Echo

GSM Manufacturer Info
  * AT+CGMI - Manufacturer Information
  * AT+CGMM - Manufacturer Model
  * AT+CGMR - Manufacturer Revision

GSM Configuration
  * AT+ICF  - Control Character Framing
  * AT+IPR  - Fixed Local Rate (baud rate)
  * AT+IFC  - Data Flow Control

Network Command
  * AT+CPIN - PIN required
  * AT+CSQ  - Signal Quality
  * AT+COPS - Operator Selection

SMS Command
  * AT+CMGF - Message Format
  * AT+CMGS - Send SMS
  * AT+CMGR - Read SMS
  * AT+CMGD - Delete SMS
  * AT+CMGDA - Delete All SMS