Nginx HTTP Server - Fourth Edition

On the syntax

There are two major Apache directives that are important when it comes to porting rewrite rules to Nginx. Other directives have no equivalent, are not supported on purpose, or their behavior is already incorporated in the Nginx equivalent directives:

• RewriteCond: This allows you to define conditions that should be matched for the request URI to be rewritten
• RewriteRule: This performs the actual request URI rewrite by specifying a regular expression pattern, the rewritten URI, and a set of flags

The first of those directives, RewriteCond, is equivalent to Nginx's if. It is used for verifying conditions before applying a rewrite rule. The following example ensures that the requested file does not exist (!-f flag) before rewriting ...