How To: Manually update OS X time from Command Line
Sometimes OS X’s time and date gets out of sync with the real world, and using the option “Set date and time automatically:” doesn’t always work.
You can use this command in terminal to update it manually:
The server address can be any of the Apple Servers such as time.apple.com or the free Time Servers, pool.ntp.org.
This same command should work for most Unix/Linux Operating systems, as long as ntpdate is installed.