msmtp
NetworkPackage: msmtp
A minimal SMTP client that hands a machine's mail to an authenticated relay, without running a mail server. It is what lets cron and scripts send an alert.
What its options do in the lessons
From the same glossary the lessons render under their commands, so the two cannot disagree.
msmtp -a- Selects the account defined in the msmtp configuration (
-a default). Each account names an SMTP relay and the credential that authenticates to it.