Yes1
Yes2
Four: 4
Six: 6
Three: 3
One: 1
Zero: 0
Minus six: -6
message1
message2
Not dupe: 1
Not dupe: 0
extract1@example.com
subject1
From: extract2@example.com
Subject: subject2
From: nobody@example.com
Subject: replacementsubject

-a test
From: nobody@example.com
From: me@example.com
Subject: replacementsubject

-A test
From: nobody@example.com
Subject: catenate header test
To: nobody@example.com

test
Subject: remove From_ test

test
Subject: remove From_ test

test
From testing
From: nobody@example.com
Subject: add From_ test

test
From nobody@example.com
From: nobody@example.com
Subject: add From_ test

test
From: nobody@example.com
Subject: -i test
Old-Header1: value1
Header1: value1
Header2: value2

test
From: nobody@example.com
Subject: -I test
Header2: value2

test
To: nobody@example.com
In-Reply-To: <1@example.com>
References: <2@example.com>
	<3@example.com>
      <1@example.com>
Subject: Re: autoreply test

You wrote:

+Autoreply test
+Original message
old-subject: -R option test
From: nobody@example.com

-R option test
Subject: -u test, line1

Testing -u option
Subject: -u test, line2

Testing -u option