How can I use mod_rewrite to make my URLs more search engine friendly?

This FAQ explain how to change an example URL
http://www.yourdomain.com/news.php?id=24
to
http//www.yourdomain.com/news/24
to encourage search engines to index the page.

If you do NOT KNOW HOW to find and make files in your directory structure, this method is too advanced for you.

In your .htaccess file of your document root (i.e. /public_html), put the following two lines:

RewriteEngine on
RewriteRule ^news/([0-9]+)$ /news.php?id=$1

.htaccess doesn't exist by default, so you may have to create it. It's just a normal text file. Some ftp clients won't list it unless explicitly told to do so. It WILL appear in the File Manager of your control panel.

The directives above mean, in essence, "turn on the rewrite engine, and here's a rule to check for."

The RewriteRule is a regular expression that the mod_rewrite engine tries to match each and every page request to. It is always in the form of:

RewriteRule pattern-to-find substitution-to-rewrite-to [OPTIONAL FLAGS]

Each portion of the directive is separated by 1 space.

Looking at this regular expression in particular...

The first part of the directive "^news/([0-9]+)$" is the regex pattern the engine will try to match.

In this context, the "^" character means to "anchor" the regex and start the match at the beginning of the requested url.

The "news/" characters are just regular characters, and should match exactly to the requested url.

"[0-9]" means to match only digits.

The "+" means to match the preceding expression (only digits) at least 1 or more times.

The surrounding parentheses mean that the regex engine should "capture" any matches it finds within and save them for later use.

The "$" character means to "anchor" the regex to the end of the requested url.

So in plain English this might read: "Starting at the beginning of the page request string, match "news", then a forward slash, then any digits, until the end of the page request string. and save the digits for later reference."

The second part, "/news.php?id=$1", is the substitution url to rewrite the request to if the engine has matched the preceding pattern.

It is pretty self-explanatory, except for the "$1". this is a backreference to the parentheses in the pattern. think of it as a placeholder for any "captured" matches found in the preceding pattern (remember the parentheses?). Each backreference will be replaced by the corresponding parentheses in the pattern. So if you have 2 parenthetical expressions in the pattern, you can have backreferences $1 and $2 in the substitution. You can have up to 9 backreferences.

In plain English this might read: "Rewrite (and reroute) the page request you just found a match for, to news.php?id="

A Google search on "mod_rewrite" will help you find more tutorials about this method.

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