Perl Date and Time

The most suitable way to handle date and time in P erl is by using DateTime module.

Before every operation of date and time, we need to load DateTime in memory through our script.

use DateTime;

localtime()

The localtime() function if used without any argument returns the current date and time according to the system.

#!/usr/local/bin/perl
$datetime = localtime();
print "Current date and time according to the system : $datetime\n";

timestamp

A DateTime object displaying current date and time can be created by calling now constructor.

use DateTime;
my $datetime = DateTime->now;
print "$datetime\n";

We can also create a DateTime object by supplying all the details part wise like date, minute, second, etc. The perl will assume data as '0' where no detail will be passed.

use DateTime;
$datetime = DateTime->new(
    day        => 18,
    month      => 7,
    year       => 2003,
    hour       => 12,
);
print"$datetime\n";

In the above output, we haven't passed any detail for minute and second part. Hence it is assumed to be zero by Perl.

Perl GMT time, gmtime()

This function works similar to localtime() function with only difference that the gmtime() returned value is localized for the standard Greenwich time zone.

#!/usr/local/bin/perl
$gmt = gmtime();
print "$gmt\n";
$local = localtime();
print "$local\n";

Epoch time

The epoch time refers to the number of seconds after a specific date and time. This specific date and time varies for different operating systems. For example, for Unix it is January 1, 1970. As all the operating systems have different epoch time, you can't assume epoch time for one system from another system.

#!/usr/local/bin/perl
$epoch = time();
print "$epoch\n";

POSIX Function strftime()

The Perl POSIX strftime() function is used to format date and time with the specifiers preceded with (%) sign. There are two types of specifiers, one is for local time and other is for gmt time zone.

Local Specifiers

GMT Specifiers

Displaying Date and Time

Sometimes we need to display a date or time in different formats. To do this, we can change the format in Perl as shown below.

#!/usr/bin/env perl
use strict;
use warnings;
use 5.010;
use DateTime;
my $datetime = DateTime->new(
    day        => 18,
    month      => 7,
    year       => 2003,
    hour       => 12,
    minute     => 00,
    second     => 00,
);
say $datetime;
say $datetime->ymd;
say $datetime->ymd('_');
say $datetime->hms;
say $datetime->epoch;
say $datetime->year;
say $datetime->month;
say $datetime->day;
say $datetime->strftime( '%Y-%m-%d-%H-%M-%S' );