htaccess dynamic redirect + only if URL begins with value

Question

i need to make this: site.com/9999100 automatically turn into this: site.com/intro?pn=9999100

and it should do the same each time someones tries to typing the url with the string 9999 right after the domain name.

Any help greatly appreciated.

Answer 1

add this directive to your root .htaccess:

RewriteRule ^(9999.*)$ /intro?pn=$1 [R=301,QSA]