perl中日期模块处理

下载TimeDate模块包：TimeDate

在脚本中，加载模块包：

use Date::Parse;
use Date::Format;

设定一个标题，按一定的格式打印某天的日期：

my $yesterday = time2str("%Y%m%d", time - 3600 * 24);

其格式标准参见CPAN文档：

摘录如下：

%%      PERCENT
        %a      day of the week abbr
        %A      day of the week
        %b      month abbr
        %B      month
        %c      MM/DD/YY HH:MM:SS
        %C      ctime format: Sat Nov 19 21:05:57 1994
        %d      numeric day of the month, with leading zeros (eg 01..31)
        %e      like %d, but a leading zero is replaced by a space (eg  1..32)
        %D      MM/DD/YY
        %G      GPS week number (weeks since January 6, 1980)
        %h      month abbr
        %H      hour, 24 hour clock, leading 0's)
        %I      hour, 12 hour clock, leading 0's)
        %j      day of the year
        %k      hour
        %l      hour, 12 hour clock
        %L      month number, starting with 1
        %m      month number, starting with 01
        %M      minute, leading 0's
        %n      NEWLINE
        %o      ornate day of month -- "1st", "2nd", "25th", etc.
        %p      AM or PM
        %P      am or pm (Yes %p and %P are backwards :)
        %q      Quarter number, starting with 1
        %r      time format: 09:05:57 PM
        %R      time format: 21:05
        %s      seconds since the Epoch, UCT
        %S      seconds, leading 0's
        %t      TAB
        %T      time format: 21:05:57
        %U      week number, Sunday as first day of week
        %w      day of the week, numerically, Sunday == 0
        %W      week number, Monday as first day of week
        %x      date format: 11/19/94
        %X      time format: 21:05:57
        %y      year (2 digits)
        %Y      year (4 digits)
        %Z      timezone in ascii. eg: PST
        %z      timezone in format -/+0000