Крепление sshfs программы запуска исчезает после закрытия терминала

Any idea how can I change the 'From' field?

Используйте флаг -f.

-fname

Sets the name of the ''from'' person

Вот так:

echo "foo" | sendmail -f maulinglawns -t root@localhost

Результат:

From maulinglawns@debian10  Wed Jan 22 21:11:24 2020
Return-Path: 
Received: from debian10 (localhost [127.0.0.1])
        by debian10 (8.15.2/8.15.2/Debian-14~deb10u1) with ESMTP id 00MKBOq3005526
        for ; Wed, 22 Jan 2020 21:11:24 +0100
Received: (from root@localhost)
        by debian10 (8.15.2/8.15.2/Submit) id 00MKBO0K005511
        for root@localhost; Wed, 22 Jan 2020 21:11:24 +0100
Date: Wed, 22 Jan 2020 21:11:24 +0100
From: maulinglawns@debian10
Message-Id: 

foo