Would be nice to add an option to the mail command to be able to define the sender-envelope / the return-path mail address.
For example, GNU mail.mailutils has -r :
use address as the return address when sending mail
FreeBSD mail does not use -r yet, so it could be chosen for this purpose.
Thank you very much,
BSD mailx also has -r :
Use from-addr as the from address in the message and envelope.
Overrides any from options in the startup files.
Fix incorrect assignment.