Nginx logfiles not working?

I try to use the nginx error and access logfiles. To activate them I should use the following command. But it does not work:

access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error_log;
-bash: access_log: command not found
-bash: error_log: command not found

Need help for activating it.

you can have a look to /var/log/nginx/ if they exist.

They already exist.

did you add following to your config file

access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;

or did you try to execute it on CLI?

I tried from my terminal.

Do I have to put this into the files in /var/log/nginx/?

yes, these are configuration parameter and not CLI commands.