About to check if link exists with PHP?

[realistic]

I already know that at least 100 methods to do that but the thing is that I want to check existence of files which might be as big as 100 MBS.

So need help about the whole file and checking existence will be huge waste of bandwidth and time. Any way to solve my problem?

[immediate]

I use curl and get the http code to determine if a webpage is available at the address or not.

[silverf0x]

is curl built in PHP or I must install it ??