DateTime Commands

System time and timezone management is critical for Zal Ultra. Incorrect time causes authentication failures, billing issues, and log inconsistencies.

🟡 LOW RISK

Most datetime commands are safe for viewing. Only timezone changes require caution.

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Table of Contents

1. View Date & Time
2. Timezone Management
3. NTP Synchronization
4. Hardware Clock
5. Troubleshooting

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View Date & Time

Show Current Date and Time

date

Output: Sat Mar 8 17:30:45 UTC 2025

Show Date in Specific Format

# ISO format
date +"%Y-%m-%d %H:%M:%S"

# Custom format
date +"%d/%m/%Y %I:%M %p"

# Unix timestamp
date +%s

Show Current Timezone

timedatectl

Example Output:

               Local time: Sat 2025-03-08 17:30:45 UTC
           Universal time: Sat 2025-03-08 17:30:45 UTC
                 RTC time: Sat 2025-03-08 17:30:45
                Time zone: UTC (UTC, +0000)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

Show UTC Time

date -u

Show Timezone Abbreviation

date +%Z

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Timezone Management

List Available Timezones

timedatectl list-timezones

Search for Timezone

timedatectl list-timezones | grep -i asia
timedatectl list-timezones | grep -i dhaka
timedatectl list-timezones | grep -i karachi

Common Timezones

Region	Timezone
Bangladesh	Asia/Dhaka
Pakistan	Asia/Karachi
India	Asia/Kolkata
UAE	Asia/Dubai
UK	Europe/London
US East	America/New_York
US West	America/Los_Angeles

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Set Timezone

🟠 CAUTION

Changing timezone affects all timestamps in logs and may cause temporary confusion in billing/reports.

sudo timedatectl set-timezone Asia/Dhaka

Verify Timezone Change

timedatectl
date

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Set Timezone via Symlink (Alternative)

sudo ln -sf /usr/share/zoneinfo/Asia/Dhaka /etc/localtime

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NTP Synchronization

Check NTP Status

timedatectl status

Look for: System clock synchronized: yes

Enable NTP

sudo timedatectl set-ntp true

Disable NTP

sudo timedatectl set-ntp false

Check NTP Service

sudo systemctl status systemd-timesyncd

Force Time Sync

sudo systemctl restart systemd-timesyncd

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Using chrony (Alternative NTP)

# Install chrony
sudo apt install chrony

# Check status
chronyc tracking

# Force sync
sudo chronyc makestep

# View sources
chronyc sources

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Hardware Clock

Show Hardware Clock Time

sudo hwclock --show

Sync System Time to Hardware Clock

sudo hwclock --systohc

Sync Hardware Clock to System Time

sudo hwclock --hctosys

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Manual Time Setting

🟠 NOT RECOMMENDED

Only use if NTP is unavailable. Manual time will drift.

Set Date and Time Manually

# Disable NTP first
sudo timedatectl set-ntp false

# Set date and time
sudo timedatectl set-time "2025-03-08 17:30:00"

# Or using date command
sudo date -s "2025-03-08 17:30:00"

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Troubleshooting

Time Drifting

# Check NTP sync status
timedatectl status

# Restart NTP service
sudo systemctl restart systemd-timesyncd

# Force immediate sync
sudo systemctl stop systemd-timesyncd
sudo ntpdate pool.ntp.org
sudo systemctl start systemd-timesyncd

Wrong Timezone in PHP

# Check PHP timezone
php -i | grep timezone

# Set in php.ini
sudo nano /etc/php/8.3/fpm/php.ini
# Add: date.timezone = Asia/Dhaka

sudo systemctl restart php8.3-fpm

Wrong Timezone in MySQL

-- Check MySQL timezone
SELECT @@global.time_zone, @@session.time_zone;

-- Set timezone
SET GLOBAL time_zone = '+06:00';

Or in MySQL config:

sudo nano /etc/mysql/mysql.conf.d/mysqld.cnf
# Add: default-time-zone = '+06:00'

sudo systemctl restart mysql

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Laravel Timezone

Check .env file:

APP_TIMEZONE=Asia/Dhaka

Check config/app.php:

'timezone' => env('APP_TIMEZONE', 'UTC'),

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Quick Reference Card

Action	Command
Show date/time	date
Show timezone info	timedatectl
List timezones	timedatectl list-timezones
Set timezone	sudo timedatectl set-timezone Asia/Dhaka
Enable NTP	sudo timedatectl set-ntp true
Check NTP status	timedatectl status
Force sync	sudo systemctl restart systemd-timesyncd
Hardware clock	sudo hwclock --show
UTC time	date -u
Unix timestamp	date +%s