timedatectl — Manage time zone and clock sync

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Manages the system time zone, clock synchronization state and manual time settings.

Basic Information

What is this command?

timedatectl reports and sets the time zone and NTP synchronization state.

It is the first tool to check when log timestamps or certificate validation look wrong.

What problems does it solve?

• Align log timestamps with the operating standard.
• Verify NTP synchronization.
• Check a UTC-only operating policy.
• Disable sync before setting the clock manually.

Key features

Status

Without arguments it shows time, zone and sync state.

• When to use: Routine checks
• What you get: Current time and NTP state
• Limitations: Sync state alone does not prove accuracy

Time zone change

set-timezone changes the system time zone.

• When to use: When adopting the standard zone
• What you get: Logs and services use the new zone
• Limitations: Some services may need a restart

NTP control

set-ntp enables or disables automatic synchronization.

• When to use: When diagnosing sync problems
• What you get: Sync activation changed
• Limitations: Offline hosts may drift

Installation and usage

Check whether it is installed

timedatectl --version

systemctl --version # systemd must be PID 1

Real-world examples

Status

Show time and sync state.

# Show current time settings
 timedatectl

Set time zone

Switch to the Seoul zone.

# Change the system time zone
sudo timedatectl set-timezone Asia/Seoul

Enable NTP

Enable automatic sync.

# Enable NTP synchronization
sudo timedatectl set-ntp true