Apache mod_rewrite rule

Let's see what the following lines mean:

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*) index.php

The RewriteRule ^(.*) index.php will redirect everything entered from "http://www.my-domain.com" to index.php so that we can parse the URI.

The two lines above it:

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d

means that if the file with the specified name in the browser doesn't exist, or the directory in the browser doesn't exist, then proceeds to the rewrite rule below the two lines:

RewriteRule ^(.*) index.php

Therefore, index.php will be used if a file or a directory is not available.

To enforce a no-trailing-slash policy:

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)/$ /$1 [L,R=301]

To enforce a trailing-slash policy:

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*[^/])$ /$1/ [L,R=301]

When permanently moving a web site, or a web page, best practice is to use a 301 redirect. 302 means a temporary redirect, and it's the default.

Here is a sample of redirecting http to https for a subdomain:

<VirtualHost *:443>
        ServerAdmin webmaster@localhost
        ServerName subdomain.mydomain.com

        DocumentRoot /var/www/home/myroot
        SSLEngine on
        SSLCertificateFile /etc/apache2/ssl-cert/mydomain.crt
        SSLCertificateKeyFile /etc/apache2/ssl-cert/mydomain.key
        SSLCertificateChainFile /etc/apache2/ssl-cert/gd_bundle.crt

        ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
        <Directory "/usr/lib/cgi-bin">
                AllowOverride None
                Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
                Order allow,deny
                Allow from all
        </Directory>

        ErrorLog ${APACHE_LOG_DIR}/error.log

        # Possible values include: debug, info, notice, warn, error, crit,
        # alert, emerg.
        LogLevel warn

        CustomLog ${APACHE_LOG_DIR}/access.log combined

    Alias /doc/ "/usr/share/doc/"
    <Directory "/usr/share/doc/">
        Options Indexes MultiViews FollowSymLinks
        AllowOverride None
        Order deny,allow
        Deny from all
        Allow from 127.0.0.0/255.0.0.0 ::1/128
    </Directory>

</VirtualHost>

<VirtualHost *:80>
    ServerName subdomain.mydomain.com
    Redirect "/" "https://subdomain.mydomain.com"
</VirtualHost>

Note we need to add ServerName and VirtualHost block with 80.