October 2022
Beginner to intermediate
390 pages
7h 5m
Chinese
Content preview from Perl语言入门（第8版）
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268
第
15
章
进程管理
身为程序员最棒的一面，就是能运行别人的程序，不必自己动手去写。现在，我们来
学习一下如何从
Perl
直接启动其他程序并管理这些子进程。
在
Perl
里有种说法：“办法不止一种”，这里也是如此。这些办法可能有许多重叠或
差异，且各有特色。如果你不喜欢头一种方法，大可往下读个一两页，找到比较合胃
口的方式。
Perl
的可移植性非常高。本书的其他章节大都不需要用脚注来说明某个程序在
Unix
上是这样，在
Windows
上是那样，而在
VMS
上又是另外一种情况。但当你想在自己
的计算机上运行别人的程序时，请注意：在
Macintosh
上能找到的程序与老式的
Cray
（曾经是“超级”计算机）上的多半大不相同。本章的例子将以
Unix
环境为主，如
果你使用的不是
Unix
系统，难免会碰到一些差异。
system
函数
在
Perl
中启动子进程最简单的方法是用
system
函数。比如要从
Perl
调用
Unix
的
date
命令，告诉
system
要运行的外部程序的名字即可：
system 'date';
这类命令来自操作系统，它们能提供什么以及如何实现都依赖操作系统。它们不是
Perl
的附带品，但
Perl
可以请求操作系统调用它们。同样作用的
Unix
命令的调用惯
例及选项在不同版本、不同种类的操作系统上都会有所差异。
进程管理
｜
269
如果在
Windows
上执行上面的代码，会显示当前日期时间，并且继而提示输入新的
日期以便更新。然后程序就挂在那边等待输入。我们可以使用 ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.