I try to use Getopt::Long to get options, and test it: 
use Getopt::Long;

my ( $timeout, $show_help ) = 30;
unless ( GetOptions("timeout|t=i" => \$timeout, "help|h|?" => \$show_h
+elp) && $show_help ) {
    error_info();
}

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I means, if GetOptions can get the right options and find --help option ，it should show the help info output by error_info(). or if GetOptions failed to get the right options, some errors happend, it also should show the help info. but when I execute the script likes below: 
my.pl --help

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there's no output, so why?

In reply to why this not work? by zapp_prefect

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