Programming Perl, 4th Edition

localtime

localtime EXPR
localtime

This function converts the value returned by time to a nine-element list with the time corrected for the local time zone. It’s typically used as follows:

#  0    1    2     3     4    5     6     7     8
($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime;

If, as here, EXPR is omitted, it does localtime(time()).

All list elements are numeric and come straight out of a struct tm. (That’s a bit of C programming lingo—don’t worry about it.) In particular, this means that $mon has the range 0..11 with January as month 0, and $wday has the range 0..6 with Sunday as day 0. You can remember which ones are zero-based because those are the ones you’re always using as subscripts into zero-based arrays containing month and day names.

For example, to get the name of the current day of the week:

$thisday = (qw(Sun Mon Tue Wed Thu Fri Sat))[(localtime)[6]];

$year is the number of years since 1900; that is, in year 2023, $year is 123, not simply 23. To get the four-digit year, just say $year + 1900. To get the two-digit year (for example, “01” in 2001), use sprintf("%02d", $year % 100).

The Perl library module Time::Local contains a subroutine, timelocal, that can convert in the opposite direction.

In scalar context, localtime returns a ctime(3)-like string. For example, the date(1) command can be (almost)^[239] emulated with:

perl –le 'print scalar localtime()'

See also the standard POSIX module’s strftime function for a more fine-grained approach to formatting times. The Time::localtime ...