REBOL [
    Title: "Print Mailbox Subjects"
    File:  %mbxsubjects.r
    Date:  4-June-1999
    Author: "Carl Sassenrath"
    Purpose: {
        Prints all the mail subject lines for a Eudora mailbox file.
    }
]

mailbox: read %in.mbx

;-- Determine the marker for message separation:
first-line: copy/part mailbox find mailbox newline
parts: parse first-line ""
marker: reform [parts/1 parts/2]

parse mailbox [
    some [thru marker thru newline copy message to marker
        (mail: import-email message print mail/subject)]
]