调用shell_exec("php myscript.php")进入无限循环 [英] calling shell_exec("php myscript.php") goes into infinite loop

问题描述

我决定派出我的php脚本，因为它运行时间太长.当我在本地linux计算机上运行shell_exec()调用时，我没有看到无限循环问题，但是在托管计算机上，脚本进入了无限循环.我将代码减少到最低限度，希望有人可以帮助我在这里查看问题:

I decided to fork out my php script because it takes too long to run. When I ran it shell_exec() call on a local linux machine, I did not see the infinite loop problem, but on a hosted machine, the script went into an infinite loop. I reduced the code to the minimum and I hope someone can help me see the problem here:

涉及3个脚本:
test_shell.php->将shell_exec()颁发给forkphp.sh->发出命令"path/to/php write_hello_world.php"

3 scripts are involved:
test_shell.php --> issues shell_exec() to forkphp.sh --> which issues a command "path/to/php write_hello_world.php"

从上到下的顺序，首先是test_shell.php脚本:

starting from top to bottom order, first the test_shell.php script:

<?php
    if(function_exists('shell_exec')) {
            echo "shell_exec() is enabled";
    }

    $cmd = "./forkphp.sh > /dev/null 2>&1 &";
    echo "<br/> About to shell_exec($cmd)<br/>";
    $out = shell_exec($cmd);
    echo $out;

?>

这是forkphp.sh:

Here is forkphp.sh:

#!/bin/bash
# About to run /usr/bin/php  write_hello_world.php
echo $(/usr/bin/php write_hello_world.php)

最后，这是write_hello_word.php:

Finally, here is write_hello_word.php :

<?php
$data = "This is a test : testing \n testing \n ";

file_put_contents ("deleteme.txt",$data);

?>

这将导致一个无限循环，其中文件'deleteme.txt'不断被重写.我只是在猜我可能在某个地方误用了"$"? 预先感谢您的帮助.

This gets an infinite loop where file 'deleteme.txt' continuously re-written . I am only guessing that I maybe misusing the '$' somewhere? Thank you in advance for help.

推荐答案

通过 FILE_APPEND 标志标记为file_put_contents()，否则文件将被一次又一次覆盖:

Pass the FILE_APPEND flag to file_put_contents(), otherwise the file would being overwritten again and again:

file_put_contents ("deleteme.txt",$data, FILE_APPEND);

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