.htaccess Redirect/Rewrite Tutorial

Part 1 - How do I redirect all links for www.domain.com to domain.com ?

Description of the problem:
Your website can be accessed with www.domain.com and domain.com. Since Google penalizes this due to duplicated content reasons, you have to stick your domain to either www.domain.com or domain.com.
But - since some links are outside of your website scope and the search engines already have indexed your website under both addresses, you can't change that easily.

Solution:
Do a 301 redirect for all http requests that are going to the wrong URL.

Example 1 - Redirect domain.com to www.domain.com

Example 2 - Redirect www.domain.com to domain.com

Explanation of this .htaccess 301 redirect
Let's have a look at the example 1 - Redirect olddomain.com to www.newdomain.com. The first two lines just say apache to handle the current directory and start the rewrite module. The next line RewriteCond %{HTTP_HOST} !newdomain.com$ specifies that the next rule only fires when the http host (that means the domain of the queried URL) is not (- specified with the "!") newdomain.com. The $ means that the host ends with newdomain.com - and the result is that all pages from newdomain.com will trigger the following rewrite rule. Combined with the inversive "!" is the result every host that is not newdomain.com will be redirected to this domain. The [NC] specifies that the http host is case insensitive. The escapes the "." - becaues this is a special character (normally, the dot (.) means that one character is unspecified). The next - and final - line describes the action that should be executed: RewriteRule ^(.*)$ http://www.newdomain.com/$1 [L,R=301]. The ^(.*)$ is a little magic trick. Can you remember the meaning of the dot? If not - this can be any character (but only one). So .* means that you can have a lot of characters, not only one. This is what we need - because this ^(.*)$ contains the requested URL, without the domain. The next part http://www.newdomain.com/$1 describes the target of the rewrite rule - this is our "final", used domain name, where $1 contains the content of the (.*). The next part is also important, since it does the 301 redirect for us automatically: [L,R=301]. L means this is the last rule in this run - so after this rewrite the webserver will return a result. The R=301 means that the webserver returns a 301 moved permanently to the requesting browser or search engine.

Part 2 - How do I redirect domain.com/ to domain.com/index.php ?

Description of the problem:
You have a website with the name domain.com - and you want to redirect all incomming URL's that are going to domain.com/ to domain.com/index.php

Solution

Explanation of this .htaccess 301 redirect
What does this code above do? Let's have a look at the example 1 - Redirect olddomain.com to www.newdomain.com. The first two lines just say apache to handle the current directory and start the rewrite module. The next line RewriteCond %{HTTP_HOST} !newdomain.com$ specifies that the next rule only fires when the http host (that means the domain of the queried url) is not (- specified with the "!") newdomain.com. The $ means that the host ends with newdomain.com - and the result is that all pages from newdomain.com will trigger the following rewrite rule. Combined with the inversive "!" is the result every host that is not newdomain.com will be redirected to this domain. The [NC] specifies that the http host is case insensitive. The escapes the "." - becaues this is a special character (normally, the dot (.) means that one character is unspecified). The next - and final - line describes the action that should be executed: RewriteRule ^(.*)$ http://www.newdomain.com/$1 [L,R=301]. The ^(.*)$ is a little magic trick. Can you remember the meaning of the dot? If not - this can be any character(but only one). So .* means that you can have a lot of characters, not only one. This is what we need - because this ^(.*)$ contains the requested url, without the domain. The next part http://www.newdomain.com/$1 describes the target of the rewrite rule - this is our "final", used domain name, where $1 contains the content of the (.*). The next part is also important, since it does the 301 redirect for us automatically: [L,R=301]. L means this is the last rule in this run - so after this rewrite the webserver will return a result. The R=301 means that the webserver returns a 301 moved permanently to the requesting browser or search engine.

Part 3 - How can I migrate domain content with .htaccess?

Description of the problem:
You have an old website that is accessible under olddomain.com and you have a new website that is accessible under newdomain.com . Copying the content of the old website to the new website is the first step - but what comes after that? You should do a 301 moved permanently redirect from the old domain to the new domain - which is easy and has some advantages:

• Users will automatically be redirected to the new domain - you don't have to inform them.
• Also search engines will be redirected to the new domain - and all related information will be moved to the new domain (but this might take some time).
• Google's PageRankTM will be transfered to the new domain, also other internal information that is being used to set the position of pages in the search engine result pages (serp's) - like TrustRank .

Solution:
Do a 301 redirect for all http requests that are going to the old domain.

Example 1 - Redirect from olddomain.com to www.newdomain.com

This is useful when you use www.newdomain.com as your new domain name (see also this article about redirecting www and non-www domains). If not - use the code of example 2.

Example 2 - Redirect from olddomain.com to newdomain.com

Part 4 - Add a trailing slash to requested URLs

Description of the problem:
Some search engines remove the trailing slash from URL's that look like directories - e.g. Yahoo does it. But this could result into duplicated content problems when the same page content is accessible under different URL's. Apache gives some more information in the Apache Server FAQ.

Let's have a look at an example: enarion.net/google/ is indexed in Yahoo as enarion.net/google - which would result in two URL's with the same content.

Solution
The solution was to create a .htaccess rewrite rule that adds the trailing slashes to these URL's. Example - redirect all URL's that doesn't have a trailing slash to URL's with a trailing slash

Explanation of this add trailing slash .htaccess rewrite rule
The first line tells Apache that this is code for the rewrite engine of the mod_rewrite module of Apache. The 2nd line sets the current directory as page root. But the interesting part is following now: RewriteCond %{REQUEST_FILENAME} !-f makes sure that files that are existing will not get a slash added. You shouldn't do the same with directories since this would exclude the rewrite behavior for existing directories. The line RewriteCond %{REQUEST_URI} !example.php exludes a sample URL that shouldn't be rewritten. This is just an example - if you don't have any file or URL that shouldn't be rewritten, remove this line. The condition RewriteCond %{REQUEST_URI} !(.*)/$ finally fires when a URL doesn't contain a trailing slash - this is all what we want. Now we need to redirect these URL with the trailing slash: RewriteRule ^(.*)$ http://domain.com/$1/ [L,R=301] does the 301 redirect to the URL with the trailing slash appended for us. You should replace domain.com with your URL. Make sure that you stick with the right domain name; if unsure, have a look at this article.