Just write ntp at command prompt: this command will give no response nor returns a prompt but leaves you the ability to write on the terminal. I tried to write some random commands, help included, with no help, but, magically, after you exit with a [ctrl]+c you get again the prompt and the system date updates.
Unfortunately, due to the fact that the ntp command leaves the terminal in a dumb mode I'm not confident in adding it to a startup script.
Code:
ntpclient -h time.nrc.ca -s