perl 知识点积累

$|=1;    # turn off I/O buffering

$$;  # 当前pid

$" = "\n"; # 行分隔符

eval
push  (  @program,'$i = 1;');
push ( @program,'$i = 3; $j = 2; $k = $i + $j');
push ( @program, '$i = 3; return 24; $k = $i + $j');
foreach $exp (@program)
{
    $rtn =eval($exp);
    print $rtn,"\n";
}
Output:
1
5
24