ntpdate

Synchronize and set date and time

$ sudo ntpdate [host]

$ ntpdate -q [host]

$ sudo ntpdate -u [host]

$ sudo ntpdate -b [host]

ntpdate [options] server...

ntpdate sets the system date and time by querying NTP (Network Time Protocol) servers. It performs a one-time synchronization, unlike ntpd which runs continuously.
By default, if the time offset is small, ntpdate gradually adjusts (slews) the clock to avoid disrupting running programs. For large offsets, it steps the clock immediately. The -b flag forces stepping regardless of offset size.
Multiple servers can be specified; ntpdate queries all and uses the best response.

-q

Query only; don't set the clock

Use unprivileged port for outgoing packets (useful for firewalls)

Force time to be stepped (abrupt change) rather than slewed (gradual)

Log to syslog instead of stdout

Verbose output

Debug mode; don't change time, show what would happen

Timeout for server response in seconds

Deprecated in favor of ntpd -q or sntp. Abrupt time changes (-b) can confuse applications expecting monotonic time. Requires root privileges to set the system clock. Not suitable for continuous synchronization; use ntpd or chronyd instead.

ntpdate was part of the original NTP distribution but has been deprecated since NTP 4.2.8. Modern systems typically use systemd-timesyncd, chrony, or ntpd for time synchronization.

ntpd(8), chronyc(1), timedatectl(1), sntp(8)