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+Date: Mon, 28 Sep 2015 20:55:36 -0400\r
+Message-ID:\r
+ <CAJhTkNgwX8cmsKfJGV+x7HHMXPNZvXFXO=KZzLvrcWCGrDL=Pg@mail.gmail.com>\r
+Subject: correct way to search for only PDF attachments\r
+From: Xu Wang <xuwang762@gmail.com>\r
+To: notmuch@notmuchmail.org\r
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+\r
+Hi,\r
+\r
+I would look to look for all emails from a colleague jongho. I tried:\r
+\r
+from:jongho attachment:pdf\r
+\r
+which seems to do as I wanted.\r
+\r
+To understand more, what does the following search for?\r
+\r
+from:jongho attachment:.*pdf\r
+\r
+I know it is incorrect as the results tell me, but what exactly does it do?\r
+\r
+Also, how does the first one above know that I want only PDF\r
+attachments and not an attachment called "pdformula.txt" ?\r
+\r
+Kind regards,\r
+\r
+Xu\r