timedatectl

Timedatectl is a command-line utility provided by systemd for querying and controlling the system clock, time zone, and related time settings on Linux systems that use systemd. It interacts with the systemd-timedated service (and timesyncd on many installations) to manage time configuration in a centralized, consistent way.

The tool supports both inspection and modification of time parameters. Users can view current values such as local time, universal time, hardware clock (RTC) time, the configured time zone, whether the system clock is synchronized, and the status of NTP services. It can also modify settings, including setting the system time, changing the time zone, enabling or disabling NTP synchronization, and configuring whether the hardware clock runs in UTC or local time.

Common usages include:

- timedatectl status or simply timedatectl to display current settings.

- timedatectl set-time "YYYY-MM-DD HH:MM:SS" to set the system time.

- timedatectl set-timezone ZONE to change the time zone (for example, Europe/Berlin).

- timedatectl set-ntp true|false to enable or disable NTP synchronization.

- timedatectl set-local-rtc true|false to configure whether the hardware clock is kept in local time or UTC.

- timedatectl list-timezones to view available time zones.

- timedatectl timesync-status to query the status of the active time synchronization daemon.

- timedatectl show to output detailed property values.

Notes: modifying time settings typically requires elevated privileges. Timedatectl reflects the behavior of the underlying time services on the host; on some distributions chrony may be used instead of timesyncd, with occasional differences in reporting. It is included by default on most systemd-based distributions.