use File::Tee;
my $logfile = "log.txt";
File::Tee::tee STDOUT, { mode => '>>', lock => 1, open => $logfile };

# I tried to untie STDOUT but it did not work
#untie STDOUT

&pager();

sub pager { 
        my $temp = "temp.txt";
        my $pager = "less"; 
        system("$pager $temp");
}