notmuch copy custom header (hack)

gistfile1.sls

(defun ks-notmuch-show-copy-entry-url ()
      (interactive)
      (let ((raw (shell-command-to-string 
                  (concat notmuch-command 
                          " show --format=raw "
                          (notmuch-show-get-message-id)))))
        (if (string-match "X-Entry-URL: \\(.*\\)" raw)
            (let ((url (match-string 1 raw)))
              (kill-new url)
              (message "Killed url: %s" url))
          (error "No X-Entry-URL header present"))))