$ echo "
Sender: 123

Recipient:  aaa

Date: 2009/03/04

Content: data0039

Time: 08:20:01

Operator: test

Subject: test01

Content: data data

Subject: RE: test

Content: data2 data

Additional: additional data
" | perl -ne'
if ( 1 .. $content && /^Subject/ ) {
    $content += /^Content/;
    print;
    }
'

Sender: 123

Recipient:  aaa

Date: 2009/03/04

Content: data0039

Time: 08:20:01

Operator: test

Subject: test01
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