NB-IoT Shield/HAT for Raspberry Pi

Can I gather data from the NB-IoT network (several NB-IoT nodes) through a Linux machine as a gateway? I try to understand, when I mount the Sixfab NB-IoT node on raspberry pi, it turns to end-device, and sending data to Linux machine (as local-server UDP/TCP) to cloud?

Yes. NB-IoT Shield turns the RPi to end-device. And you can send data to a remote or local Linux server (machine). But NB-IoT technology use only UDP protocol to provide the feature of low power consumption.