Perl

$random = rand(100);

sprintf "%.3f", $random;  ##小数点后面保留3位。

time

localtime(time); ##Thu Dec 23 13:25:02 2011
gmtime(time); ##Thu Dec 23 00:25:02 2011
time; ##1196347834

($sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst) = localtime(time);


Subroutines
sub doit
{
......
}

$value = 10;
if($value<10){
doit;
}