In this post we will learn about how to set date and time as well as how to get date and time information with date command.
Note: If you want to set date and time of system you must be login with superuser or root.

Date command is one of the useful command in linux. At the end I will show you some examples which are generally used by Server Admins.
Date command can also be used as timezone converter , “use date command as a timezone converter“

How to see system date and time

To see the system date and time,use the given below command i.e date .

linux@tuxworld:~$ date
Tue Jul  2 19:50:40 IST 2013
linux@tuxworld:~$ 

How to set Date and Time

To set the date and time of system use the format with date command i.e date MonthDateHourMinute

In this example I set the date and time , July 02 08:01 p.m

root@tuxworld:~# date
Tue Jul  2 19:56:32 IST 2013
root@tuxworld:~# 
root@tuxworld:~# date 07022001
Tue Jul  2 20:01:00 IST 2013
root@tuxworld:~# 

There is another method, You can also set the date and time by using strings. Below are the examples.
date --set="Write-your-strings-as-per-given-below-examples"

(In this example if you do not set time,it will start with 00:00 means 12'O clock midnight)
root@tuxworld:~# date --set="July 02 2013"
Tue Jul  2 00:00:00 IST 2013

root@tuxworld:~# date --set="July 02 2013 20:10:01"
Tue Jul  2 20:10:01 IST 2013

OR

root@tuxworld:~# 
root@tuxworld:~# date --set="07/02/2013 20:10:01"
Tue Jul  2 20:10:01 IST 2013

OR

root@tuxworld:~# date --set="02-July-2013 20:10:15"
Tue Jul  2 20:10:15 IST 2013
root@tuxworld:~#
 
OR

root@tuxworld:~# date --set="20130702 20:15:01"
Tue Jul  2 20:15:01 IST 2013
root@tuxworld:~#

How To Set Only Time

You can also set only time by using –set flag

root@tuxworld:~# date --set="20:15:01"
Tue Jul  2 20:15:01 IST 2013
root@tuxworld:~# 

Using flags to get specific output from date command

There are many flags which you can use with date command to get specific information.
I will recommend you once read the man page of date man date. We are sharing a few examples which will help you a lot.

Syntax

date +%format-flag

Date Command Examples

Example 1

In this example, I want to see only date but having hyphen(-) sign in between

root@tuxworld:~# date +%F
2013-07-02
root@tuxworld:~# 

Example 2

See the date and having separated by slash (/)

root@tuxworld:~# date +%D
07/02/13
root@tuxworld:~#

Example 3

Now I want to see only weekday in Full words or abbreviation

root@tuxworld:~# date +%b
Jul
root@tuxworld:~# date +%B
July
root@tuxworld:~# 

Example 4

To see the time

root@tuxworld:~# date +%T
20:31:22
root@tuxworld:~#
root@tuxworld:~# date +%R
20:31
root@tuxworld:~# 

Example 5

Now check this %n is for new line here and %t for new tab

root@tuxworld:~# date '+DATE: %m/%d/%y%nTIME:%H:%M:%S'
DATE: 07/02/13
TIME:20:32:48
root@tuxworld:~# 
root@tuxworld:~# date '+DATE: %m/%d/%y%tTIME:%H:%M:%S'
DATE: 07/02/13	TIME:20:33:53
root@tuxworld:~# 

Example 6

To see only timezone with date command

root@tuxworld:~# date +%Z
IST
root@tuxworld:~#

Date Command While Taking Backup Of Files

For example we want to take backup of file by using cp command means copy . Here we are using backticks ( ` ).
You can play with date command for many purposes it depends upon your task.

Example 1

In this example, copy the file and appending date as suffix in file name. It is like taking backup of file. It helps to identify on which date the file was backup.

root@tuxworld:/tmp# ls -l data_list
-rw-r--r-- 1 root root 0 Jul  2 20:38 data_list
root@tuxworld:/tmp# 
root@tuxworld:/tmp# cp -p data_list data_list.`date +%F`
root@tuxworld:/tmp# ls -l data_list*
-rw-r--r-- 1 root root 0 Jul  2 20:38 data_list
-rw-r--r-- 1 root root 0 Jul  2 20:38 data_list.2013-07-02
root@tuxworld:/tmp# 

Example 2

In this example, we are using Date command in bash script. It will create the mysql dump(backup) and also append date with the mysql dump file name.

#!/bin/bash
mysqldump -u username -p password database-name > database-name-backup.`date +%F`.sql

Check Date Command Version

To check the version of date command apply the following command.

root@tuxworld:~# date --version
date (GNU coreutils) 8.13
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later .
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by David MacKenzie.
root@tuxworld:~# 

Do you want to know how we can use the Date command for converting the TimeZone. Read our this article “Use Date As A TimeZone Converter“