htaccess RewriteRule, mod_rewrite, RewriteCond & Redirect 301

Redirecting from a WWW Domain to a non-WWW Domain

# 301 redirect(permanent redirect) from http://www.sample.com to http://sample.com
RewriteEngine on
Options +FollowSymLinks
RewriteCond %{HTTP_HOST} ^www.sample.tld$ [NC]
RewriteRule ^(.*)$ http://sample.com/$1 [R=301,L]

Redirecting from One Domain to Another Domain

Suppose we want to redirect all the pages & posts of http://www.sample1.com to http://www.sample2.com. To do this, you just have to place the below code in .htaccess file of http://www.sample1.com.

# redirect from http://www.sample1.com to http://www.sample2.com
RewriteEngine On
RewriteRule ^(.*)$ http://www.sample2.com/$1 [R=301,L]

Redirect 301

301 redirect is also known as permanent redirect. It redirects visitors to new page as well as it signals search engine bots that the page has been moved permanently to a new location.

Redirecting a page to a different location –

Here I am redirecting URL http://sample.com/category1/page1.html to http://sample.com/category2/page2.html

# 301 Redirect example
Redirect 301 /category1/page1.html http://sample.com/category2/page2.html

It can also be written as –

Redirect permanent /category1/page1.html http://sample.com/category2/page2.html

In the above example we are setting up a redirection within the same site. If you are planning to setup a redirect between two different websites then RewriteRule is a better option.

Example –
I’m using the same example of sample1 and sample2

# RewriteRule
RewriteRule http://www.sample1.com/firstpage.php http://www.sample2.com/secondpage.php
RewriteRule http://www.sample1.com/category/ http://www.sample2.com/mynewcat/
RewriteRule http://www.sample1.com/ http://www.sample2.com/

Redirect whole website to a new Domain’s homepage

Say, the below code is placed in sample1’s .htaccess file, then any requested url for sample1 would be redirected to the sample2’s home page (i.e. http://www.sample2.com/)

# permanent redirect for a whole site
Redirect 301 / http://www.sample2.com

The above code can also be written as –

Redirect permanent / http://www.sample2.com

Redirect if File doesn’t exist

If my file – http://sample.com/category/page.php doesn’t exist then redirect to http://sample.com/category2/subcat/. Lets write it in .htaccess file –

# rewrite only if the file doesn't exist
RewriteCond %{REQUEST_URI} ^/category/(.*)/page.php$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^category/(.*)/page.php$ category2/subcat/$1

Redirect to SubDomain

For example, I want to redirect my visitors to http://mysub.sample.com from http://sample.com then you can write it as-

# send visitors to a subdomain
RewriteCond %{HTTP_HOST} !^$
RewriteCond %{HTTP_HOST} !^subdomain.domain.com$ [NC]
RewriteRule ^/(.*)$ http://mysub.sample.com/$1 [L,R=301]

Fix duplicate content issue using rewrite

For example – my website www.sample.com has a webpage which would be displayed when user enters any of the below url in browser –
http://www.sample.com/mypage
http://www.sample.com/mypage?id=94

If you consider the SEO then these pages may be treated as duplicate pages so to avoid such situation you can redirect the pages of second type to the first one.

RewriteCond %{THE_REQUEST} ^GET /.*;.* HTTP/
RewriteCond %{QUERY_STRING} !^$
RewriteRule .* http://www.sample.com%{REQUEST_URI}? [R=301,L]

After having the above code in .htaccess, when user enters the url – http://www.sample.com/mypage?id=94, it would be redirected to the – http://www.sample.com/mypage