InfoUnix

Linux · Solaris · DevOps

Linux · Lesson

Date and Time Commands in Linux

Add the YouTube embed URL for this lesson in components/linux/linuxLessons.js.

Why date and time management matters

Correct system date and time settings are extremely important in Linux environments. Logs, scheduled jobs, authentication and distributed applications all depend on accurate time settings.

Linux provides several utilities such as date, cal and timedatectl for managing system time and timezone configuration.

Core date and time concepts

System time

Linux maintains system time used by applications, logs, scheduled tasks and services.

Calendar utilities

Commands like cal help administrators quickly view monthly and yearly calendars.

Timezones

Linux supports multiple global timezones and allows administrators to switch between them.

Step-by-step Linux date and time commands

Practice the following commands in your Linux lab to understand how date, time and timezone management works.

1. Check current date and time

The date command displays the current system date, time and timezone.

terminal — bash

linux-lab

[root@localhost ~]# date
Thu Dec 19 04:51:11 PM IST 2024
[root@localhost ~]# 

2. Print current month's calendar

The cal command shows the calendar for the current month.

terminal — bash

linux-lab

[root@localhost ~]# cal
    December 2024
Su Mo Tu We Th Fr Sa
 1  2  3  4  5  6  7
 8  9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31
 
[root@localhost ~]# 

3. Display calendar for a specific year

You can print the full calendar for any year using cal <year>.

terminal — bash

linux-lab

[root@localhost ~]# cal 2026
 
                            2026
 
      January               February               March
Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa  Su Mo Tu We Th Fr Sa
             1  2  3   1  2  3  4  5  6  7   1  2  3  4  5  6  7
 
[root@localhost ~]# 

4. Display calendar for a specific month

Use cal with a month name to display that month’s calendar.

terminal — bash

linux-lab

[root@localhost ~]# cal March
 
     March 2024
Su Mo Tu We Th Fr Sa
                1  2
 3  4  5  6  7  8  9
10 11 12 13 14 15 16
 
[root@localhost ~]# 

5. Display current time only

Use formatting options with date to print only the time.

terminal — bash

linux-lab

[root@localhost ~]# date +%H:%M:%S
16:58:30
[root@localhost ~]# 

6. Display current month name

The +%B format option prints the full month name.

terminal — bash

linux-lab

[root@localhost ~]# date +%B
December
[root@localhost ~]# 

7. Display current day name

The +%A format option prints the current weekday name.

terminal — bash

linux-lab

[root@localhost ~]# date +%A
Thursday
[root@localhost ~]# 

8. Display timezone offset

The +%z option shows the current timezone offset from UTC.

terminal — bash

linux-lab

[root@localhost ~]# date +%z
+0530
[root@localhost ~]# 

9. Set system date and time

Root users can manually update the system date and time.

terminal — bash

linux-lab

[root@localhost ~]# date -s "2024-12-19 17:20:00"
Thu Dec 19 05:20:00 PM IST 2024
[root@localhost ~]# 

10. Check detailed time configuration

timedatectl provides detailed information about system time and timezone settings.

terminal — bash

linux-lab

[root@localhost ~]# timedatectl
 
               Local time: Thu 2024-12-19 17:20:59 IST
           Universal time: Thu 2024-12-19 11:50:59 UTC
                 RTC time: Thu 2024-12-19 11:51:04
                Time zone: Asia/Kolkata (IST, +0530)
System clock synchronized: no
              NTP service: active
          RTC in local TZ: no
 
[root@localhost ~]# 

11. Set a new timezone

Use timedatectl set-timezone to configure a different system timezone.

terminal — bash

linux-lab

[root@localhost ~]# timedatectl set-timezone Asia/Kolkata
 
[root@localhost ~]# timedatectl
 
               Local time: Thu 2024-12-19 17:35:45 IST
                Time zone: Asia/Kolkata (IST, +0530)
 
[root@localhost ~]# 

Important command categories

Date and calendar commands

date → display or modify system date and time
cal → display monthly calendar
cal <year> → display yearly calendar
date +FORMAT → customize output formatting

Timezone management

timedatectl → display detailed time settings
timedatectl list-timezones → list all available timezones
timedatectl set-timezone → configure timezone
timedatectl status → verify synchronization status

Good administration practices

Time synchronization

Enable NTP synchronization on production systems.
Verify timezone settings after installing Linux.
Keep system clocks synchronized across servers.

Operational safety

Avoid changing system time unnecessarily on active servers.
Incorrect time settings can break logs and authentication.
Use timedatectl instead of manually editing configuration files.

Practice tasks for your Linux lab

Run date and verify your current timezone.
Display the calendar for your birth year using cal YEAR.
Print only the current month name using date +%B.
List all available timezones using timedatectl list-timezones.
Change the timezone temporarily and verify the update using timedatectl.

In upcoming lessons, you will continue learning important Linux administration commands and system-management tools.