Low-level sending of mail from file via cmdline

Question

I have a saved mail (in Maildir format) including all headers and attachments.

I would like to send this file as email (with all the given headers intact) to a new email address, something like:

$ cat mail.txt  | forwardMail [e-mail]

which should basically connect to the MTA, use [e-mail] as the "RCPT TO" and the contents of mail.txt as the DATA.

I tried things like the following, but it doesn't handle headers and attachments gracefully; also, I have to specify the subject on the cmdline (while it is already defined in mail.txt).

 $ cat mail.txt | mail -s "foo" [e-mail]

Answer 1

Pipe the message into /usr/lib/sendmail -i. (Some systems put it in /usr/sbin/sendmail instead.)

All MTAs (Postfix, Sendmail MTA, Exim, &c.) install their own version of the sendmail program, and it is the same tool that Mail and other Unix programs use to submit mail messages.

• The recipient addresses are specified in the command line. (If you add -t instead, sendmail takes the recipients from the message's headers such as To:, which you do not want this time, but it might be useful in other cases.)

• The -i option tells sendmail to disable the special treatment of lines starting with a dot; it is needed for historical reasons.

• The -f $address option can be used to change the "envelope FROM" address (not related to the From: header).