Detecting a value in a URL

[Anon]

Hi,

I'm just learning to swim in PHP...

I need to detect a word in an URL of a referring search engine's page and based on the search term used display certain message. Here's a good example of a referring URL:
http://www.google.com/search?hl=en&q=textbook+buyback

Say I need to detect BUYBACK in that string. Here's what I've tried so far:

if(ereg("\buyback",$HTTP_REFERER))
{
Header ("Location: mymessage.php");
}
else {
Header ("Location: default.php");
}

Obviously it dosn't find what I need and sends a user to default.php.

Question: How to make this script look for a specific term withing en entire URL?

I'd apreciate any ideas.

[kevinsequeira]

this should work for the url http://www.google.com/search?hl=en&q=textbook+buyback

print ($q);
if (ereg("buyback",$q)){
print("yes, has buyback");
}else{
print("no, doesnt have buyback");
}

[Anon]

Thanks!