How to find the an email is having attachments from sendmail log.

Short answer: you don't.

While both MSA and MTA apply checks they basically are only interested in finding out if a message is standards compliant and if it is deliverable. This doesn't mean you can't have a milter to store copies or test for attachments but you would have to configure those beforehand as that information isn't available in default maillog. And a milter may or may not even help. To name a few pitfalls (and these may or may not apply depending on your reasons for asking): an attachment doesn't automagically mean MIME multi-part messages, an attachment may be encrypted, information can be stored in message headers, sending an attachment doesn't necessarily mean that the sender sent it or that the recipient read it and information may leave premises in different ways.


* BTW, wrt your other thread please don't just say
but post your fix for the benefit of those that seek help later on,
TIA.