What it does
timedatectl is a systemd utility used to query and control system time, hardware clock, timezone, and NTP synchronization.
How it works (mechanical)
- Communicates with
systemd-timedated. - Reads/writes system clock settings.
- Controls NTP synchronization (if enabled).
- Manages timezone configuration.
10 Practical Examples
# 1) Show current time and status timedatectl
# 2) List available timezones timedatectl list-timezones
# 3) Set timezone sudo timedatectl set-timezone America/New_York
# 4) Enable NTP synchronization sudo timedatectl set-ntp true
# 5) Disable NTP sudo timedatectl set-ntp false
# 6) Manually set date/time sudo timedatectl set-time "2026-02-11 14:30:00"
# 7) Check if system clock is synchronized timedatectl status
# 8) Show hardware clock (RTC) mode timedatectl | grep RTC
# 9) Set RTC to local time (dual-boot systems sometimes require this) sudo timedatectl set-local-rtc 1
# 10) Reset RTC to UTC (recommended for servers) sudo timedatectl set-local-rtc 0
Notes & Gotchas
- Servers should typically use UTC (RTC in UTC).
- Dual-boot Windows systems sometimes expect local RTC time.
- NTP must be reachable for sync to succeed.
- Time drift can break Kerberos, AD logins, and certificate validation.
Historical Context
Before systemd, admins configured time via hwclock, date,
and direct edits to /etc/localtime. timedatectl centralizes and standardizes this control.
Modern Equivalent
On systemd systems, timedatectl is the standard interface.
Legacy tools include hwclock, ntpq, and chronyc.
Related Commands
- hwclock — hardware clock management
- chronyc — Chrony NTP control
- ntpq — NTP query tool
- date — basic time display/set
- systemctl — manage time services