shell_exec()

(PHP 4, PHP 5, PHP 7)

通过 shell 环境执行命令，并且将完整的输出以字符串的方式返回。

说明

本函数同执行操作符。

参数

要执行的命令。

返回值

命令执行的输出。如果执行过程中发生错误或者进程不产生输出，则返回NULL。

当进程执行过程中发生错误，或者进程不产生输出的情况下，都会返回NULL，所以，使用本函数无法通过返回值检测进程是否成功执行。如果需要检查进程执行的退出码，请使用exec()函数。

范例

Example #1shell_exec()例程

注释

当 PHP 运行在安全模式时，不能使用此函数。

参见

• exec() 执行一个外部程序
• escapeshellcmd()shell 元字符转义

If you're trying to run a command such as "gunzip -t" in shell_exec and getting an empty result, you might need to add 2>&1 to the end of the command, eg:
Won't always work:
echo shell_exec("gunzip -c -t $path_to_backup_file");
Should work:
echo shell_exec("gunzip -c -t $path_to_backup_file 2>&1");
In the above example, a line break at the beginning of the gunzip output seemed to prevent shell_exec printing anything else. Hope this saves someone else an hour or two.

To run a command in background, the output must be redirected to /dev/null. This is written in exec() manual page. There are cases where you need the output to be logged somewhere else though. Redirecting the output to a file like this didn't work for me:

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