PHP_EOL 用法 : Most Worthless Constant?

PHP_EOL may very well be the most worthless general-purpose constant in modern PHP. It's supposed to be helpful for cross-platform developing, for example you could write a PHP-powered shell script that says:

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and then expect the proper newline to terminate the output string based on the platform PHP is running on.
That's all well and good, but the following is functionally equivalent:
$str = str_replace(PHP_EOL, '', $str);
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来源： http://blog.sina.com.cn/s/blog_6dbaeb9b0100z4tt.html
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