[Unit]
Description=Htpdate daemon

[Service]
Type=forking
PIDFile=/var/run/htpdate.pid
ExecStart=/usr/bin/htpdate -D -a -s -i /var/run/htpdate.pid www.linux.org www.freebsd.org ntp.neu.edu.cn www.kernel.org

[Install]
WantedBy=multi-user.target