在Products视图操作中，您可以查看用户是否有更新或删除产品的权限，并设置用于显示或隐藏视图中按钮的变量。
In the Products view action, you could check to see if the user has permission to update or delete the product and set variables that can be used to display or hide the buttons in the view.
与shell中的其他操作一样，环境变量可以控制每次shell显示提示符时应显示的内容。
Much like other operations in the shell, an environment variable controls what's drawn each time the shell presents a prompt.
清单25显示了如何保存当前操作以及到两个XSL变量的相应元素的引用。
Listing 25 shows how to save the current action and a reference to the corresponding element in two XSL variables.
tcsh定义了一个shell变量rmstar；如果打开这个变量，在用户执行操作时会显示提示，要求用户确认操作。
Tcsh defines a shell variable rmstar; when turned on, it provides the user with a prompt that requests confirmation of the user's action.
没有X11显示变量设置，但这个程序进行操作，需要。
No X11 DISPLAY variable was set, but this program performed an operation which requires it.
比如你对一个整型变量，除非你显示的进行转化，否则你是不能像对待字符串那样就行某些操作。
If you have an integer, you can't treat it like a string without explicitly converting it.
比如你对一个整型变量，除非你显示的进行转化，否则你是不能像对待字符串那样就行某些操作。
If you have an integer, you can't treat it like a string without explicitly converting it.
应用推荐