How do I get yesterday's date in perl?

Question

Currently i take today date using below.I need to get yesterday date using this.. how can i get that ?

my $today = `date "+%Y-%m-%d"`;

Answer 1

If you want yesterday's date:

use DateTime qw( );

my $yday_date =
   DateTime
      ->now( time_zone => 'local' )
      ->set_time_zone('floating')
      ->truncate( to => 'day' )
      ->subtract( days => 1 )
      ->strftime('%Y-%m-%d');

For example, in New York on 2019-05-14 at 01:00:00, it would have returned 2019-05-13.

For example, in New York on 2019-11-04 at 00:00:00, it would have returned 2019-11-03.

Note that ->now( time_zone => 'local' )->set_time_zone('floating')->truncate( to => 'day' ) is used instead of ->today( time_zone => 'local' ) to avoid this problem.

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If you want the time a day earlier:

use DateTime qw( );

my $yday_datetime =
   DateTime
      ->now( time_zone => 'local' )
      ->subtract( days => 1 )
      ->strftime('%Y-%m-%d %H:%M:%S');

For example, in New York on 2019-05-14 at 01:00:00, it would have returned 2019-05-13 01:00:00.

For example, in New York on 2019-03-10 at 12:00:00, it would have returned 2019-03-09 12:00:00.

For example, in New York on 2019-03-11 at 02:30:00, it would have resulted in an error. 2019-03-10 02:30:00 didn't exist because of the switch to Daylight Saving Time.

---

If you want the time 24 hours earlier:

use DateTime qw( );

my $yday_datetime =
   DateTime
      ->now( time_zone => 'local' )
      ->subtract( hours => 24 )
      ->strftime('%Y-%m-%d %H:%M:%S');

For example, in New York on 2019-05-14 at 01:00:00, it would have returned 2019-05-13 01:00:00.

For example, in New York on 2019-03-10 at 12:00:00, it would have returned 2019-03-09 11:00:00.

For example, in New York on 2019-03-11 at 02:30:00, it would have returned 2019-03-10 01:30:00.