htaccess-based redirection of numeric-only URLs

Question

Let me explain by example — I want the web server to redirect a URL like http://example.com/-NUM to http://example.com/?p=NUM i.e. for instance, http://example.com/-121 should be redirected to http://example.com/?p=121.

In this case, what should the .htaccess redirection rules look like?

Answer 1

The pattern ^-(\d+)$ will match numeric URI's beginning with a hyphen and capture into $1.

RewriteEngine On
RewriteRule ^-(\d+)$ /?p=$1 [L]

If this is a PHP script, for example, you may need to use index.php as the target:

RewriteRule ^-(\d+)$ index.php?p=$1 [L]