Send mail from the commandline on Linux

Question

For testing a new mail server (Postfix) I need to send an email locally, preferably from the commandline. I know I can use netcat or telnet to talk to the SMTP service directly

me@server:~ $ telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 foo.example.com ESMTP Postfix
helo example.org
250 foo.example.com
mail from:<me@example.org>
250 2.1.0 Ok
rcpt to:<postmaster@foo.example.com>
250 2.1.5 Ok
data
354 End data with .
Subject: test

test
.
250 2.0.0 Ok: queued as A103C452
quit
221 2.0.0 Bye
Connection closed by foreign host.

but isn't there a more convenient way?

Answer 1

There are several ways, actually.

The simplest approach is most likely the sendmail command that ships with Postfix, since that does not require additional software:

from='me@example.org'
to='postmaster@foo.example.com'
subj='Foo'
msg='Your message.'

echo -e "Subject: ${subj}\n\n${msg}" | sendmail -f "$from" "$to"

Another option would be the mailx commandline utility. However, you probably need to install that first (for Debian-based systems it's in the package bsd-mailx):

from='me@example.org'
to='postmaster@foo.example.com'
subj='Foo'
msg='Your message.'

echo "$msg" | mailx -r "$from" -c '' -s "$subj" "$to"

Or you could install something like Mutt, which provides you with an ncurses-based interface. The program needs some configuration, though. Create a file .muttrc with the following content in your userhome:

# ~/.muttrc
set mbox_type=maildir
set spoolfile="/var/mail/USERNAME"
set folder="~/Mail/"

Replace USERNAME with your actual username on the system.

You can instruct the client to use a specific from address by adding this line:

set from=me@example.org

and/or make headers (including the From: header) editable by adding

set edit_hdrs=yes