Shell脚本 - PHP - 显示错误

Question

I'm using PHP function shell_exec()to execute Shell Script. When I use this(correct) syntax, it displays output normally

echo shell_exec("ls -l");

But, for some reason, if user enters invalid command like this

echo shell_exec("lsl -l");

by default, it should give error as it gives on terminal. But, it doesn't display anything. is there any way to catch and display errors as well; via PHP?

Answer 1

That's because the output of the error goes to STDERR, while shell_exec only reads STDOUT. The simplest solution would probably be to pipe STDERR to STDOUT:

<?php
echo shell_exec('lsl -l 2>&1');

If you only want to know if the command was successful, I would use exec rather than shell_exec, as you can get the return value.