Program execution 函数
PHP Manual

passthru

(PHP 4, PHP 5)

passthruExecute an external program and display raw output

说明

void passthru ( string $command [, int &$return_var ] )

The passthru() function is similar to the exec() function in that it executes a command. This function should be used in place of exec() or system() when the output from the Unix command is binary data which needs to be passed directly back to the browser. A common use for this is to execute something like the pbmplus utilities that can output an image stream directly. By setting the Content-type to image/gif and then calling a pbmplus program to output a gif, you can create PHP scripts that output images directly.

参数

command

The command that will be executed.

return_var

If the return_var argument is present, the return status of the Unix command will be placed here.

返回值

没有返回值。

注释

Warning

当用户提供的数据传入此函数,使用 escapeshellarg()escapeshellcmd() 来确保用户欺骗系统从而执行任意命令。

Note:

如何程序使用此函数启动,为了能保持在后台运行,此程序必须将输出重定向到文件或其它输出流。 否则会导致 PHP 挂起,直至程序执行结束。

Note: 安全模式 启用时,可仅可用 safe_mode_exec_dir 执行文件。实际上,现在不允许在到可执行的路径中存在 .. 组件。

Warning

安全模式 启用时,命令字符串会被 escapeshellcmd() 转换。因此, echo y | echo x 会变成 echo y \| echo x

参见


Program execution 函数
PHP Manual