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3.1. Finding Today's Date

3.1.1. Problem

You need to find the year, month, and
day values for today's date.

3.1.2. Solution

Use localtime, which
returns values for the current date and time if given no arguments.
You can either use localtime and extract the
information you want from the list it returns:

($DAY, $MONTH, $YEAR) = (localtime)[3,4,5];

or use Time::localtime, which overrides localtime
to return a Time::tm object:

use Time::localtime;
$tm = localtime;
($DAY, $MONTH, $YEAR) = ($tm->mday, $tm->mon, $tm->year);

3.1.3. Discussion

Here's how you'd print the current date as "YYYY MM DD", using the
non-overridden localtime:

($day, $month, $year) = (localtime)[3,4,5];
printf("The current date is %04d %02d %02d\n", $year+1900, $month+1, $day);
The current date is 2003 03 06

To extract the fields we want from the list returned by
localtime, we take a list slice. We could also
have written it as:

($day, $month, $year) = (localtime)[3..5];

This is how we'd print the current date as "YYYY-MM-DD" (in approved
ISO 8601 fashion), using Time::localtime:

use Time::localtime;
$tm = localtime;
printf("The current date is %04d-%02d-%02d\n", $tm->year+1900, 
($tm->mon)+1, $tm->mday);
The current date is 2003-03-06

The object interface might look out of place in a short program.
However, when you do a lot of work with the distinct values,
accessing them by name makes code much easier to understand.

A more obfuscated way that does not involve temporary variables is:

printf("The current date is %04d-%02d-%02d\n",
sub {($_[5]+1900, $_[4]+1, $_[3])}->(localtime));

There is also
strftime from the POSIX module discussed in Recipe 3.8:

use POSIX qw(strftime);
print strftime "%Y-%m-%d\n", localtime;

The gmtime function
works just as localtime does, but gives the answer
in UTC instead of your local time zone.

3.1.4. See Also

The localtime and gmtime
functions in perlfunc(1) and Chapter 29 of
Programming Perl; the documentation for the
standard Time::localtime module