[Mimedefang] Testing for the existence of a header

[Nigel Allen]

Thanks to David for the last advice - appreciated.

Can anyone please tell me how to test for the existence of a header in 
an email?

Some of the emails that flow through our server have a header - let's 
call it X-ABC whilst other do not.

I need to test for the existence of X-ABC before I try to extract the 
value of it to a variable,

Googled, searched etc etc - apologies - my perl is only exceeded by my 
good looks :(

Rgds

Nigel.