eregi to preg_match

[Kingy]

I'm creating a domain lookup script from a php class I found online.

 

Only problem with it is the fact that it uses the eregi function which I no is going out of fashion. Now i've never really used either eregi or preg_match so I have no idea how to convert one into the other.

 

if (eregi('^([a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)*[a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?$',$domain) != 1){

 

if(eregi($this->ext['.'.$domain_domain][1], $f_result)){

 

I've had a play with both of them and usually end up getting an error about using backslashes or something. I no it means that I need to escape the characters, but its just really confusing me.

 

Can anybody help me out. Thanks in advance.

[Kingy]

Ok i've managed to make the first one work. Still having confusion issues with the seond. For anyone that needs to know..

 

Before:

if (eregi('^([a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)*[a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?$',$domain) != 1){

 

After:

if (preg_match("/^([a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)*[a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?$/i", $domain) != 1){