What is the ' operator ' in PHP for?

Reply content:

The above is the representative of the garbage interpreter.
Shell as a professional term directly, should not be translated into the shell, increase misunderstanding ...

"Content is executed as a shell command.

Let's take the example above

运行了就能显示当前文件夹内容了

Please read the official PHP documentation, which is more useful than reading. It's best to look online. I've been so unified in my advice for beginners.

You have this problem with the corresponding document address http://php.net/manual/zh/language.operators.execution.php

All you need. The example is also very clear. Examples are not clear, often the following user comments will also have a very clear example (the user issued the example is mostly English, the other basically translated)

Execute shell_exec command, high-risk function, recommended to turn off
Reference: http://www.yunxi365.cn/index.php/archives/10/

"is the same as the shell_exec () function;

  You can run the Linux command. and return output;  

is a high-risk function!

  Shell:pidstat- P ' pidof Firefox '  

PHP can also be used as a shell to invoke system commands with anti-apostrophe ' or shell_exec.
In MySQL, when a database name/table name/field name and reserved word (keyword) conflict, the SQL statement is separated by a backslash (').

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