将所有Redis数据导出到Laravel中的json OR txt文件中

I am using,

exec('redis-dump 127.0.0.1:6379 > db_full.json');

but it only create '0 kb' file. I am using it in my Home Controller Constructor.

How can I do this successful export? My Framework is Laravel.

Please guide me on this. Thanks in advance.

Note: You guys are free to ask questions.