This article introduces the standard input and output of PHP, which has certain reference value. Now I share it with you. Friends in need can refer to it.

Brief introduction to the standard input and output of PHP

7 months ago⋅956 ⋅11 ⋅0

##I want to use PHP in Sphere Online Judge today I came to challenge some questions online, which requires the use of standard input and output, but I am writing PHP recently and don’t want to use C to write. I usually submit forms when writing projects. I really haven’t considered this, so I took a look at the documentation.

STDIN,STDOUT,STDERRcommand input and output streams are used to send messages to the console (linux shell terminal, windows cmd terminal) input and output content, they are open by default, you can directly read and write them, they can only be used in CLI (command-line interface, command line interface) mode, in Http mode, they are undefined.

And their open copiesphp://stdin,php://stdout,php://stderrcannot output the content to http browsing After testing, the content written tophp://stderrwill be entered into the error log of the default site, and the other two have no effect.

STDIN/STDOUT/STDERR Introduction:

It is officially recommended to use the constants STDIN, STDOUT and STDERR instead of their manually opened copy wrappersphp://stdin,php://stdoutandphp: //stderr.

2. PHP STDIN usage:

"STDIN" in PHP language is used to read content from the console. When encountering this constant or opening it through thefopen()functionphp://stdinThe script will wait for the user to enter content until the user presses the Enter key to submit.

Writestdin.phpTest it:

      
Run result:
      
请输入内容:sad 输入的内容为: sad 请输入: asdasdasdasdasdasd 输入为: asdasdasdasd（这里因为设置了最多读取12个字符，设置更多一些就可以完整显示）
      
3. PHP STDOUT usage:
      
PHP In the language,STDOUTis used to output standard information to the console; write to this constant or tophp://stdoutopened by thefopen()function. The content will be output directly to thestandard outputof the console; the content of the standard output can be redirected to the specified place using ">" or "1>" , such as files.
      
Similarly, let’s write a file to test it
      

      
Run it:
      
☁ test php demo.php > a.txt ☁ test cat a.txt 通过STDOUT写入； 通过php://stdout写入；% ☁ test php demo.php 通过STDOUT写入； 通过php://stdout写入；% ☁ test
      
4. PHP STDERR usage:
      
"STDERR" in PHP language Used to output error information to the console; content written to a constant or to "php://stderr" opened by thefopen()function will be directly output to the console'serror output; The error output content can be redirected to a specified place, such as a file, using "2>"; the error output can also be directed to standard output using "2>&1" , merged with standard output.
      
Let’s test it
      

      
Normal output and error output are directed to different files:
      
☁ test php demo.php 1>demo.ok 2>demo.err ☁ test cat demo.okSTDOUT写入的正常输出； php://stdout写入的正常输出；☁ test cat demo.errSTDERR写入的错误输出； php://stderr写入的错误输出；
      
Normal output and error output are merged and directed to a unified file:
      
☁ test php demo.php 1>AllInOne 2>&1☁ test cat AllInOneSTDERR写入的错误输出； STDOUT写入的正常输出； php://stdout写入的正常输出； php://stderr写入的错误输出；
      
Okay, now you can go to Sphere Online Judge to test the demo topic first
      

      
Write a code
      

      
Submit
      

      
Hahahaha, it’s totally ok. I no longer need to be limited to Java and C. I can challenge some questions with PHP. You can also try it
      
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Complete notes on PHP’s Smarty
      
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php download function
      
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