Sending mail in terminal's Local Mail System

instead of ctrl-c, use ctrl-z.

In any case, man mail, man sendmail, man postfix.

 

And man patience. Might want to read up on that a bit.

 

end with a period then return or ctrl d

 

Control z puts the current process (mail) in the background. It did not actually stop. The purpose is to let you use the terminal for other commands while mail waits. the "fg" command will "foreground" the background process.

What you want is to send the "end of file" character "cntl-d".

There is no special "terminal" mail system. You should be able to send outbound mail via port 25 using "mail".

If you want to learn even more use a program that hides even less of the mail protocol from you. try "telnet" to port 25. I've done this many times but mostly while debugging mail server setups. basically you just type the SMTP protocol at the server.

 

You are right. My bad.
Alternatively, just type a "." at the start of a line.