iRedMail NginX配置文件更新

Question

Referring the guides Using iRedMail with NginX and Setting up iRedMail with NginX , I'd like to ask that in the server block

server {
listen 80; server_name mail.mydomain.com;

location / {
        rewrite ^ https://$server_name$1 permanent;
}

location ~ \.php$ {
        fastcgi_pass   unix:/var/run/php5-fpm.sock;
        fastcgi_index  index.php;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME /usr/share/apache2$fastcgi_script_name;
}

}

I want to just remove the /usr/share/apache2 directory using
$ sudo apt-get remove apache2
or
$ sudo rm -rf /usr/share/apache2

therefore in the NginX iRedMail config, can I replace the following line
fastcgi_param SCRIPT_FILENAME /usr/share/apache2$fastcgi_script_name;
with
fastcgi_param SCRIPT_FILENAME /usr/share/nginx$fastcgi_script_name;
or with
fastcgi_param SCRIPT_FILENAME /etc/nginx$fastcgi_script_name; #I can see a file named fastcgi_params at /etc/nginx/

Secondly, I'd be interested in knowing how does the variable $fastcgi_script_name gets resolved?

Answer 1

I've figured out how the variable $fastcgi_script_name gets resolved.
According to my understanding, it basically replaces it with the value of $fastcgi_index, which in turn is index.php in the above case. The recommended line is:
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

However, for that it needs to have the root variable defined either inside the location {} scope or the outer server {} scope. Since, it is not defined in either of the above mentioned server block therefore for the time being I'm going to stick to:
fastcgi_param SCRIPT_FILENAME /usr/share/nginx/html$fastcgi_script_name;