timedatectl Command in Linux: Syntax, Options & Practical Examples (systemd)

Before changing time settings, check what the host thinks the clock is doing — zone, whether NTP is on, and if the journal considers the clock synchronized.

Run the command:

timedatectl status

Sample output:

Local time: Wed 2026-07-01 19:06:22 IST
           Universal time: Wed 2026-07-01 13:36:22 UTC
                 RTC time: Wed 2026-07-01 13:07:18
                Time zone: Asia/Kolkata (IST, +0530)
System clock synchronized: no
              NTP service: active
          RTC in local TZ: no

NTP service: active means synchronization is enabled — System clock synchronized: no can appear briefly until the first successful poll. Fix clock drift before package managers complain about "Release file not valid yet" errors.

Lab docs and screenshots often need a different zone for a minute. Save the current zone, set a new one, verify, then put the original back.

ORIG_TZ=$(timedatectl show -p Timezone --value)
echo "Original zone: $ORIG_TZ"
sudo timedatectl set-timezone UTC
timedatectl show -p Timezone --value
timedatectl status | grep 'Time zone'
sudo timedatectl set-timezone "$ORIG_TZ"
timedatectl show -p Timezone --value

Sample output (middle section):

Original zone: Asia/Kolkata
UTC
                Time zone: UTC (UTC, +0000)
Asia/Kolkata

Always restore $ORIG_TZ on shared hosts. Applications pick up the new zone immediately — no reboot required.

set-timezone expects an IANA name such as Europe/London, not a three-letter abbreviation like IST. Search the built-in list instead of guessing.

List all zones (long output) or filter:

timedatectl list-timezones | grep -E '^Europe/London$|^UTC$'
timedatectl list-timezones | grep Kolkata

Sample output:

Europe/London
UTC
Asia/Kolkata

Copy the full Region/City string into sudo timedatectl set-timezone Zone. See also the Ubuntu set timezone guide for GUI and file-based alternatives.

show exposes the same facts as status but as Key=value lines — easier for scripts than parsing the banner.

Print everything:

timedatectl show

Sample output:

Timezone=Asia/Kolkata
LocalRTC=no
CanNTP=yes
NTP=yes
NTPSynchronized=no
TimeUSec=Wed 2026-07-01 19:06:22 IST
RTCTimeUSec=Wed 2026-07-01 18:37:18 IST

One property, value only:

timedatectl show -p Timezone --value
timedatectl -p Timezone -p NTP --value show

Sample output:

Asia/Kolkata
yes

Use -p repeatedly or --value when you only need a single field in a pipeline.

Turn NTP off for a controlled manual clock change, then turn it back on so the host stays accurate.

Check current state, disable, re-enable:

timedatectl show -p NTP --value
sudo timedatectl set-ntp false
timedatectl show -p NTP --value
sudo timedatectl set-ntp true
timedatectl show -p NTP --value

Sample output:

yes
no
yes

On Ubuntu, set-ntp true usually activates systemd-timesyncd. Some servers use chrony instead — NTP may still show yes while timesyncd is inactive; check your distro's default NTP daemon if sync never succeeds.

When the clock will not settle, timesync-status shows the peer, poll interval, and packet count for systemd-timesyncd.

Run the command:

timedatectl timesync-status

Sample output:

Server: 185.125.190.58 (ntp.ubuntu.com)
Poll interval: 34min 8s (min: 32s; max 34min 8s)
 Packet count: 0

Low packet count right after boot is normal. If the server line is missing, timesyncd may not be running — inspect with systemctl status systemd-timesyncd.

show-timesync dumps unit properties — fallback servers, poll limits, and frequency correction — for deeper debugging than timesync-status.

Run the command:

timedatectl show-timesync | head -8

Sample output:

FallbackNTPServers=ntp.ubuntu.com
ServerName=ntp.ubuntu.com
ServerAddress=185.125.190.57
RootDistanceMaxUSec=5s
PollIntervalMinUSec=32s
PollIntervalMaxUSec=34min 8s
PollIntervalUSec=32s
Frequency=0

Pair this with timedatectl --monitor when you need a live stream of sync events during firewall or DNS changes.

RTC in local TZ: no means the hardware clock stores UTC — the recommended Linux default. Set set-local-rtc true only for dual-boot with Windows, which historically expected local time on the CMOS clock.

Read the current mode:

timedatectl status | grep 'RTC in local'
timedatectl show -p LocalRTC --value

Sample output:

RTC in local TZ: no
no

Flipping RTC mode affects firmware clock interpretation. If you must change it, use --adjust-system-clock so the running system time stays consistent:

sudo timedatectl set-local-rtc false --adjust-system-clock

Revert only when you deliberately changed the mode for dual-boot testing — on pure Linux servers, leave LocalRTC=no.