perl函数"timelocal"跟"timegm"的区别

 #!/usr/bin/perl
 use warnings;
 use strict;
 use Time::Local;
 
 ## [11/Jun/2012:23:12:03 +0800] -> 12345667 -> 2012-06-11 23:12:03
 
 my %monhash = ("Jan"=>1,"Feb"=>2,"Mar"=>3,"Apr"=>4,"May"=>5,"Jun"=>6,"Jul"=>7,"Aug"=>8,"Sep"=>9,"Oct"=>10,"Nov"=>11,"Dec"=>12);
 sub to_Stand_time {
         my $str = shift @_;
         my ($sec, $min, $hour, $day, $mon, $year, $wday, $yday, $isdst) = localtime($str);
         $year = 1900 + $year;
         $mon = $mon + 1;
         return sprintf("%s-%02d-%02d %02d:%02d:%02d",$year,$mon,$day,$hour,$min,$sec);
 }
 while(<>){
         chomp;
         if(m|^\[(\d+)/(\w+)/(\d+):(\d+):(\d+):(\d+)\s+\+\d+\]$|){
                 my($d,$m,$y,$h,$mm,$s)=($1,$2,$3,$4,$5,$6);
                 $m = $monhash{$m};
                 my $ud = Time::Local::timelocal($s,$mm,$h,$d,$m-1,$y-1900);
                 my $dt = to_Stand_time($ud);
                 print STDERR "$_ -> $ud -> $dt\n";
         }
 }