ntpd: add page (#12682)

pages/linux/ntpd.md

@@ -0,0 +1,16 @@
+# ntpd
+
+> The official NTP (Network Time Protocol) daemon to synchronize the system clock to remote time servers or local reference clocks.
+> More information: <https://manned.org/ntpd>.
+
+- Start the daemon:
+
+`sudo ntpd`
+
+- Synchronize system time with remote servers a single time (quit after synchronizing):
+
+`sudo ntpd --quit`
+
+- Synchronize a single time allowing "Big" adjustments:
+
+`sudo ntpd --panicgate --quit`