php函数file_exits,copy,shell_exec不能在一台机器上运行,但在不同的机器上运行相同的代码

I am a Centos 7 machine on which I have configured PHP with Apache and Slim Framework.

The simple code to check if the file exists and copy the code into a directory is working fine on one of the machine but not working on another machine. Its really weird.

Actually I am accessing the API through Apache to trigger this function.

Functions like shell_exec alaways return 0 copy function is also not workingg file_exists also not working.

Any help or clue why this is wrong or debug this issue.

Thanks all for the help.

Problem was file permission issue. The reason was all of the above function I was performing was on the file. Since the files has different permission for different user.

So If I hit the URL from browser it was through "Apache" user which does not have execute permission on the folder to access the file and read permission on the file.

In short

sudo chmod +rx file

sudo chmod +x "All the directory structure"