The ntpdate command is a tool used to synchronize the system date and time with the NTP (Network Time Protocol) server(s) specified as arguments. It can be run manually as necessary to set the system clock, or it can be run from a cron script to periodically update the system clock. The ntpdate command has the following syntax:
ntpdate [options] server [server ...]
The ntpdate command obtains a number of samples from each server and applies a subset of the NTP clock filter and selection algorithms to select the best one. It then adjusts the system clock either by stepping it (if the offset is larger than 0.5 seconds) or by slewing it (if the offset is smaller than 0.5 seconds). The ntpdate command can also be used to query the date and time from a server without setting the system clock by using the -q option.
The other statements are false because:
* It is not the primary management command for the NTP time server. The primary management command for the NTP time server is ntpd, which is a daemon that runs continuously and disciplines the system clock using sophisticated algorithms.
* It updates both the local system's date and time, not just the date. The ntpdate command sets the system date and time according to the configured timezone information.
* It does not send the local system time to any remote NTP time servers. The ntpdate command only queries the time from the servers and does not transmit any time information to them.
* It cannot be used by any user to set the user clock independently of the system clock. The ntpdate command must be run as root on the local host and it affects the system clock for all users.
References:
* Linux ntpdate Command Tutorial - LinuxTect
* ntpdate - set the date and time via NTP
* How to Use NTPDATE to Sync Time in Ubuntu Linux? - TheITBros

mailq, /usr/bin/mailq, sendmail -bp, /usr/sbin/sendmail -bp, /usr/lib/sendmail -bp, sendmail,
/usr/sbin/sendmail, /usr/lib/sendmail