Beginner Setup Bitcoin Full Node without GUI I am following the installation steps to setup a bitcoin node, at the steps "Download the blockchain" that required Bitcoin Core GUI which is not able to run on the testing Ubuntu Server without GUI. 

The guideline I am following is https://bitcoin.org/en/full-node#ubuntu-1610. At the Ubuntu Installation, under Bitcoin Core GUI.


Is there any command to trigger the download without GUI? Thank you very much.
In the very same guide you linked, follow the instructions for the Bitcoin daemon.


  I tried to start the daemon and hope it will download the data but it seems nothing change on H.D. usage so I am guessing it is not downloading. Am I correct?


No, you are not correct. You should check the status of bitcoind itself by using bitcoin-cli to send commands to it. You can use getblockchaininfo to know whether it is actually syncing by calling it twice. If it is syncing, then it will report a different block height and best block hash on the second call.