Configuring Time Sync on VMware Guest OS via command line

Windows:
enable VMware time sync where it was previously disabled:

vmwareservice --cmd "vmx.set_option synctime 0 1"

...and to turn it back off:

vmwareservice --cmd "vmx.set_option synctime 1 0"

GNU/Linux:

turn it on...
vmware-guestd --cmd "vmx.set_option synctime 0 1"

...and turn it back off:
vmware-guestd --cmd "vmx.set_option synctime 1 0" 

Source: http://communities.vmware.com/message/617188;jsessionid=BE639AD9083D6D03FCF4390BD2434568