[Sieve] How to retrieve part of message as a variable

I need to retrieve some parts of a message which looks like

Subject: Test message Message-Id: 2788db2f-b5c3-4b8c-881e-362c3df4f915@server.local Mime-Version: 1.0 Content-Type: multipart/report; boundary="----=_Part_fba0c199dfcd4d60ae506b37a6320a84"; report-type=disposition-notification To: adam@test.local Date: Mon, 17 Sep 2018 16:21:45 -0400 (EDT) From: postmaster@server.local

------=_Part_fba0c199dfcd4d60ae506b37a6320a84 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit

BTW, this is the correct notification ... it should be "failed" not "failure". ------=_Part_fba0c199dfcd4d60ae506b37a6320a84 Content-Type: message/notification Content-Transfer-Encoding: 7bit

Final-Recipient: rfc822; eve@test.local Original-Message-ID: 06dbfc12-57a5-49bd-84bd-a24bc3ba1e42@fake.cernerasp

------=_Part_fba0c199dfcd4d60ae506b37a6320a84—

for an example I need to grab what is after “Final-Recipient: rfc822;” and “Original-Message-ID:” and store them as variables

Thanks