How to format date for display or to use in a shell script

Q. How do I format date to display on screen on for my scripts as per my requirements?

A. You need to use standard date command to format date or time for output or to use in a shell script.

Syntax to specify format
date +FORMAT

Task: Display date in mm-dd-yy format

Type the command as follows:
$ date +"%m-%d-%y"
Output:

02-27-07

Turn on 4 digit year display:
$ date +"%m-%d-%Y"
Just display date as mm/dd/yy format:
$ date +"%D"

Task: Display time only

Type the command as follows:
$ date +"%T"
Output:

19:55:04

Display locale’s 12-hour clock time
$ date +"%r"
Output:

07:56:05 PM

Display time in HH:MM format:
$ date +"%H-%M"

How do I save time/date format to a variable?

Simply type command as follows at a shell prompt:
$ NOW=$(date +"%m-%d-%Y")
To display a variable use echo / printf command:
$ echo $NOW
Sample shell script:

#!/bin/bash
NOW=$(date +"%m-%d-%Y")
FILE="backup.$NOW.tar.gz"
# rest of script

Complete list of FORMAT control characters supported by date command

FORMAT controls the output.It can be the combination of any one of the following:

%%

a literal %

%a

locale's abbreviated weekday name (e.g., Sun)

%A

locale's full weekday name (e.g., Sunday)

%b

locale's abbreviated month name (e.g., Jan)

%B

locale's full month name (e.g., January)

%c

locale's date and time (e.g., Thu Mar 3 23:05:25 2005)

%C

century; like %Y, except omit last two digits (e.g., 21)

%d

day of month (e.g, 01)

%D

date; same as %m/%d/%y

%e

day of month, space padded; same as %_d

%F

full date; same as %Y-%m-%d

%g

last two digits of year of ISO week number (see %G)

%G

year of ISO week number (see %V); normally useful only with %V

%h

same as %b

%H

hour (00..23)

%I

hour (01..12)

%j

day of year (001..366)

%k

hour ( 0..23)

%l

hour ( 1..12)

%m

month (01..12)

%M

minute (00..59)

%n

a newline

%N

nanoseconds (000000000..999999999)

%p

locale's equivalent of either AM or PM; blank if not known

%P

like %p, but lower case

%r

locale's 12-hour clock time (e.g., 11:11:04 PM)

%R

24-hour hour and minute; same as %H:%M

%s

seconds since 1970-01-01 00:00:00 UTC

%S

second (00..60)

%t

a tab

%T

time; same as %H:%M:%S

%u

day of week (1..7); 1 is Monday

%U

week number of year, with Sunday as first day of week (00..53)

%V

ISO week number, with Monday as first day of week (01..53)

%w

day of week (0..6); 0 is Sunday

%W

week number of year, with Monday as first day of week (00..53)

%x

locale's date representation (e.g., 12/31/99)

%X

locale's time representation (e.g., 23:13:48)

%y

last two digits of year (00..99)

%Y

year

%z

+hhmm numeric timezone (e.g., -0400)

%:z

+hh:mm numeric timezone (e.g., -04:00)

%::z

+hh:mm:ss numeric time zone (e.g., -04:00:00)

%:::z

numeric time zone with : to necessary precision (e.g., -04, +05:30)

%Z

alphabetic time zone abbreviation (e.g., EDT)

See also:

• Shell Scripting: Creating report/log file names with date in filename

• Tweet
• 
• 

You should follow me on twitter here or grab rss feed to keep track of new changes.

Featured Articles:

• 30 Handy Bash Shell Aliases For Linux / Unix / Mac OS X
• Top 30 Nmap Command Examples For Sys/Network Admins
• 25 PHP Security Best Practices For Sys Admins
• 20 Linux System Monitoring Tools Every SysAdmin Should Know
• 20 Linux Server Hardening Security Tips
• Linux: 20 Iptables Examples For New SysAdmins
• Top 20 OpenSSH Server Best Security Practices
• Top 20 Nginx WebServer Best Security Practices
• 20 Examples: Make Sure Unix / Linux Configuration Files Are Free From Syntax Errors
• 15 Greatest Open Source Terminal Applications Of 2012
• My 10 UNIX Command Line Mistakes
• Top 10 Open Source Web-Based Project Management Software
• Top 5 Email Client For Linux, Mac OS X, and Windows Users
• The Novice Guide To Buying A Linux Laptop