How do I format the date to display on the screen on for my shell scripts as per my requirements on Linux or Unix like operating systems?
You need to use the standard date command to format date or time in Linux or Unix shell scripts. You can use the same command with the shell script. This page shows how to format date in Linux or Unix-based system.
| Tutorial details | |
|---|---|
| Difficulty level | Easy |
| Root privileges | No |
| Requirements | date command |
| Category | Commands |
| OS compatibility | FreeBSD • Linux • macOS • NetBSD • OpenBSD • Unix • WSL |
| Est. reading time | 8 minutes |
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Linux Syntax To Format Date For Display On Screen
The syntax is as follows for the GNU/date and BSD/date command:$ date +FORMAT
$ date +"%FORMAT"
$ date +"%FORMAT%FORMAT"
$ date +"%FORMAT-%FORMAT"
$ date -d "DATE STRING" +"%FORMAT"
$ TZ="TIMEZONE" date -d "DATE STRING" +"%FORMAT"
An operand with a leading plus (+) sign signals a user-defined format string which specifies the format in which to display the date and time. The following examples are tested on GNU/Linux, Apple OS X Unix, and FreeBSD unix operating system.
Task: Display date in mm-dd-yy format
Open a terminal and type the following date command:$ date +"%m-%d-%y"
Sample outputs:
02-27-07
To 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 following command:$ date +"%T"
Sample outputs:
19:55:04
To display locale’s 12-hour clock time, enter:$ date +"%r"
Sample outputs:
07:56:05 PM
To display time in HH:MM format, type:$ date +"%H-%M"
Sample outputs:
00-50
How do I save time/date format to the shell variable?
Simply type the following command at the shell prompt to get the current date in MM-DD-YYYY format:$ NOW=$(date +"%m-%d-%Y")
To display a variable use the following simple commands to output on screen under Linux and UNIX using the printf command/echo command:$ echo "$NOW"
$ printf "%s\n" $NOW
A sample shell script
#!/bin/bash NOW="$(date +"%m-%d-%Y")" FILE="backup.$NOW.tar.gz" echo "Backing up data to /nas42/backup.$NOW.tar.gz file, please wait..." # rest of the script ... # tar xcvf /nas42/backup.$NOW.tar.gz /home/ /etc/ /var #... #..
A complete list of FORMAT control characters supported by the GNU/date command
It can be the combination of any one of the following:
| %FORMAT String | Description |
|---|---|
| %% | 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) |
A complete list of FORMAT control characters supported by the BSD/date command
The following works on Apple macOS/OS X, FreeBSD and *BSD version of the date command:
| %FORMAT String | Description |
|---|---|
| %A | is replaced by national representation of the full weekday name. |
| %a | is replaced by national representation of the abbreviated weekday name. |
| %B | is replaced by national representation of the full month name. |
| %b | is replaced by national representation of the abbreviated month name. |
| %C | is replaced by (year / 100) as decimal number; single digits are preceded by a zero. |
| %c | is replaced by national representation of time and date. |
| %D | is equivalent to “%m/%d/%y”. |
| %d | is replaced by the day of the month as a decimal number (01-31). |
| %E* %O* | POSIX locale extensions. The sequences %Ec %EC %Ex %EX %Ey %EY %Od %Oe %OH %OI %Om %OM %OS %Ou %OU %OV %Ow %OW %Oy are supposed to provide alternate representations. Additionally %OB implemented to represent alternative months names (used standalone, without day mentioned). |
| %e | is replaced by the day of the month as a decimal number (1-31); single digits are preceded by a blank. |
| %G | is replaced by a year as a decimal number with century. This year is the one that contains the greater part of the week (Monday as the first day of the week). |
| %g | is replaced by the same year as in “%G”, but as a decimal number without century (00-99). |
| %H | is replaced by the hour (24-hour clock) as a decimal number (00-23). |
| %h | the same as %b. |
| %I | is replaced by the hour (12-hour clock) as a decimal number (01-12). |
| %j | is replaced by the day of the year as a decimal number (001-366). |
| %k | is replaced by the hour (24-hour clock) as a decimal number (0-23); single digits are preceded by a blank. |
| %l | is replaced by the hour (12-hour clock) as a decimal number (1-12); single digits are preceded by a blank. |
| %M | is replaced by the minute as a decimal number (00-59). |
| %m | is replaced by the month as a decimal number (01-12). |
| %n | is replaced by a newline. |
| %O* | the same as %E*. |
| %p | is replaced by national representation of either “ante meridiem” (a.m.) or “post meridiem” (p.m.) as appropriate. |
| %R | is equivalent to “%H:%M”. |
| %r | is equivalent to “%I:%M:%S %p”. |
| %S | is replaced by the second as a decimal number (00-60). |
| %s | is replaced by the number of seconds since the Epoch, UTC (see mktime(3)). |
| %T | is equivalent to “%H:%M:%S”. |
| %t | is replaced by a tab. |
| %U | is replaced by the week number of the year (Sunday as the first day of the week) as a decimal number (00-53). |
| %u | is replaced by the weekday (Monday as the first day of the week) as a decimal number (1-7). |
| %V | is replaced by the week number of the year (Monday as the first day of the week) as a decimal number (01-53). If the week containing January 1 has four or more days in the new year, then it is week 1; otherwise it is the last week of the previous year, and the next week is week 1. |
| %v | is equivalent to “%e-%b-%Y”. |
| %W | is replaced by the week number of the year (Monday as the first day of the week) as a decimal number (00-53). |
| %w | is replaced by the weekday (Sunday as the first day of the week) as a decimal number (0-6). |
| %X | is replaced by national representation of the time. |
| %x | is replaced by national representation of the date. |
| %Y | is replaced by the year with century as a decimal number. |
| %y | is replaced by the year without century as a decimal number (00-99). |
| %Z | is replaced by the time zone name. |
| %z | is replaced by the time zone offset from UTC; a leading plus sign stands for east of UTC, a minus sign for west of UTC, hours and minutes follow with two digits each and no delimiter between them (common form for RFC 822 date headers). |
| %+ | is replaced by national representation of the date and time (the format is similar to that produced by date(1)). |
| %-* | GNU libc extension. Do not do any padding when performing numerical outputs. |
| %_* | GNU libc extension. Explicitly specify space for padding. |
| %0* | GNU libc extension. Explicitly specify zero for padding. |
| %% | is replaced by %. |
A sample date session
I am running commands on macOS/OS X and FreeBSD:
date date +"%T" date +"%D" date +"%m-%d-Y" date "+%Y%m%d%H%M.%S"
Fig.01: date command in action
Format given date
Say you want to print “April 23, 1978” as dd/mm/yyyy:$ date -d "April 23, 1978" +"%d/%m/%Y"
Here is syntax for macOS or BSD/date command to print “April 23, 1978” as dd/mm/yyyy:$ date -j -f "%INPUT_FORMAT" date_string +"%OUTPUT_FORMAT"
$ date -j -f "%Y%m%d" 19780423 +"%d/%m/%Y"
Let us print the following date in YYYY/mm/dd format in EDT timezone:$ TZ="EDT" date -d "April 23, 2078 5:15:10 PM EDT" +"%Y/%m/%d"
The TZ shell variable determine the timezone in which the time and date are written. For example:$ TZ='TIMZ_ZONE_HERE'
$ TZ='TIMZ_ZONE_HERE' date ...
$ TZ="IST" date # Indian Standard Time
$ TZ="EST" date # Eastern Time (ET)
$ TZ='Australia/Melbourne' date # AEDT
On Linux you can list all timezone using the ls command or tzselect command. For instance:$ ls /usr/share/zoneinfo/
Africa Arctic Australia CET Cuba Eire Etc GB GMT+0 Greenwich Iceland iso3166.tab Japan leap-seconds.list MET MST7MDT NZ-CHAT Portugal PRC ROC SystemV UCT UTC zone1970.tab America Asia Brazil Chile EET EST Europe GB-Eire GMT-0 Hongkong Indian Israel Kwajalein Libya Mexico Navajo Pacific posix PST8PDT ROK Turkey Universal WET zone.tab Antarctica Atlantic Canada CST6CDT Egypt EST5EDT Factory GMT GMT0 HST Iran Jamaica leapseconds localtime MST NZ Poland posixrules right Singapore tzdata.zi US W-SU Zulu
Passing the --debug on GNU/date
We can annotate the parsed date, and warn about questionable usage to screen. For example:$ date --debug -d "April 23, 1978" +"%d/%m/%Y"
Outputs:
date: parsed date part: (Y-M-D) 1978-04-23 date: input timezone: system default date: warning: using midnight as starting time: 00:00:00 date: starting date/time: '(Y-M-D) 1978-04-23 00:00:00' date: '(Y-M-D) 1978-04-23 00:00:00' = 262117800 epoch-seconds date: timezone: system default date: final: 262117800.000000000 (epoch-seconds) date: final: (Y-M-D) 1978-04-22 18:30:00 (UTC) date: final: (Y-M-D) 1978-04-23 00:00:00 (UTC+05:30) 23/04/1978
How to set TZ permanently
Say you want your TZ shell variable set to Africa/Algiers time zone, then you can make this change permanent for yourself by appending the line to the .profile or ~/.bash_profile file. in your home directory and then log out and log in again. For example:
TZ='Africa/Algiers'; export TZ
