Store data from Adafruit Bluefruit LE UART Friend?

I'm currently working on a project with the Adafruit Bluefruit LE UART Friend and I was wondering how I would go about storing the bytes that are sent from the app when the BLE module is in Command mode.
I need send bytes to phone by using its GATT service. However, it only can be done in Command mode. I also need receive bytes from the phone app. The code showed in datasheet is AT+BLEUARTRX. I tried manually typed the command and the BLE received data showed in Serial monitor. However, when I used the command in the example

if (ble.isConnected())
    if (strcmp(ble.buffer, "OK") == 0) {
      // no data
    // Some data was found, its in the buffer
    Serial.print(F("[Recv] ")); 

It return nothing.
I also need to know how can I restore the number that the BLE received.
it returns the bytes that I typed in the phone now.
new question, How can I receive a string and store it to arduino?
Thank you!

How can I receive a string

One character at a time. Although it would appear that ble.readline() manages that for you.

and store it to arduino?

It appears that is is already stored in ble.buffer.