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Perl Cookbook by Nathan Torkington, Tom Christiansen

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Converting Epoch Seconds to DMYHMS

Problem

You have a date and time in Epoch seconds, and you want to calculate individual DMYHMS values from it.

Solution

Use the localtime or gmtime functions, depending on whether you want the date and time in GMT or your local time zone.

($seconds, $minutes, $hours, $day_of_month, $month, $year,
    $wday, $yday, $isdst) = localtime($time);

The standard Time::timelocal and Time::gmtime modules override the localtime and gmtime functions to provide named access to the individual values.

use Time::localtime;        # or Time::gmtime
$tm = localtime($TIME);     # or gmtime($TIME)
$seconds = $tm->sec;
# ...

Discussion

The localtime and gmtime functions return strange year and month values; the year has 1900 subtracted from it, and is the month value for January. Be sure to correct the base values for year and month, as this example does:

($seconds, $minutes, $hours, $day_of_month, $month, $year,
    $wday, $yday, $isdst) = localtime($time);
printf("Dateline: %02d:%02d:%02d-%04d/%02d/%02d\n",
    $hours, $minutes, $seconds, $year+1900, $month+1,
    $day_of_month);

We could have used the Time::localtime module to avoid the temporary variables:

use Time::localtime;
$tm = localtime($time);
printf("Dateline: %02d:%02d:%02d-%04d/%02d/%02d\n",
    $tm->hour, $tm->min, $tm->sec, $tm->year+1900,
    $tm->mon+1, $tm->mday);

See Also

The localtime function in perlfunc(1) and Chapter 3 of Programming Perl; the documentation for the standard Time::localtime and Time::gmtime modules; convert in ...

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