摘要：$_这个特殊变量是许多Perl函数的默认参数,也是许多Perl控制结构的默认控制变量. $_特殊变量也可当作一个函数调用缺失的参数来使用.foreach 结构的控制变量是可选的,默认为$_的值. Perl把最近发生的系统错误消息保存在特殊变量$!中. #! /usr/local/bin/perl -W#fig05_03.plforeach $name('Amanda','Jeff','Sarah'... 阅读全文

摘要：Using batch parametersYou can use batch parameters anywhere within a batch file to extract information about your environment settings.Cmd.exe provides the batch parameter expansion variables %0 through %9. When you use batch parameters in a batch file, %0 is replaced by the batch file name, and %1 阅读全文