HOST

Hostname or IP address of the SMTP server to connect to.

$ sendsmtp smtp.example.com me@example.com you@example.com -m "hi"

FROM

Sender address, used both as the SMTP envelope sender (MAIL FROM) and as the From: header.

TO

Recipient address, or several addresses separated by commas — no spaces around the commas.

$ sendsmtp smtp.example.com me@example.com "a@example.com,b@example.com" -m "hi"

-m MESSAGE, --message MESSAGE

Message body, given inline.

$ sendsmtp smtp.example.com me@example.com you@example.com -m "Deploy finished."

-i INPUT, --input INPUT

Path to a file to read the message body from. Takes precedence over --message. If the path is not an existing file the option is ignored and the body is taken from --message or from stdin instead.

$ sendsmtp smtp.example.com me@example.com you@example.com -i report.txt

If neither --message nor --input is given, the body is read from stdin. Piped input is read to EOF:

$ dmesg | tail -n 20 | sendsmtp smtp.example.com me@example.com you@example.com -s "dmesg"

When stdin is a terminal, sendsmtp prompts and reads lines until a line containing only EOF:

$ sendsmtp smtp.example.com me@example.com you@example.com
Please, provide message contents. Type 'EOF' for end.
First line.
Second line.
EOF
Message successfully sent.

--html

Send the body as text/html instead of text/plain. The body itself is taken from --message, --input or stdin as usual — the flag only changes the content type, nothing is escaped or wrapped.

$ sendsmtp smtp.example.com me@example.com you@example.com \
    -s "Report" -i report.html --html

No plain-text alternative part is generated: the message is a single text/html part, so clients that refuse HTML show it as markup.

-s SUBJECT, --subject SUBJECT

Message subject.

$ sendsmtp smtp.example.com me@example.com you@example.com -s "Nightly build" -m "green"

If --subject is not given and the body starts with a Subject: line, that line is stripped from the body and used as the subject:

$ printf 'Subject: From the body\n\nBody text.\n' \
    | sendsmtp smtp.example.com me@example.com you@example.com

-p PORT, --port PORT

SMTP port. Defaults depend on the security mode: 25 for plain, 587 with --starttls, 465 with --tls.

$ sendsmtp smtp.example.com me@example.com you@example.com -p 2525 -m "hi"

-t, --tls

Use implicit TLS — the connection is encrypted from the first byte (SMTPS, port 465 by default). Mutually exclusive with --starttls.

$ sendsmtp smtp.example.com me@example.com you@example.com -t -u me@example.com -m "hi"

--starttls

Connect in plain text and upgrade the connection with the STARTTLS extension (port 587 by default). Mutually exclusive with --tls.

$ sendsmtp smtp.example.com me@example.com you@example.com --starttls -u me@example.com -m "hi"

--allow-untrusted

Skip TLS certificate verification: the server certificate is not checked against the trust store and its hostname is not matched. Only affects --tls and --starttls. Insecure — anyone on the path can impersonate the server — so use it only for servers with a self-signed certificate you cannot add to the system trust store.

$ sendsmtp smtp.internal me@example.com you@example.com --starttls --allow-untrusted -m "hi"

-u USERNAME, --username USERNAME

Username for SMTP authentication. Without it no AUTH is attempted.

--password PASSWORD

Password for SMTP authentication. If --username is given but --password is not, the password is asked for interactively and is not echoed — preferable, since command lines are visible to other processes and land in the shell history.

$ sendsmtp smtp.example.com me@example.com you@example.com --starttls -u me@example.com -m "hi"
me@example.com's passwd:

Authentication failures abort the run; the message is not sent.

-c CC, --cc CC

Carbon-copy recipient(s), comma separated. The addresses appear in the CC: header and receive the message.

$ sendsmtp smtp.example.com me@example.com you@example.com -c "boss@example.com" -m "hi"

-b BCC, --bcc BCC

Blind carbon-copy recipient(s), comma separated. They receive the message but are not listed in any header.

$ sendsmtp smtp.example.com me@example.com you@example.com -b "archive@example.com" -m "hi"

-a PATH, --attach PATH

Attach a file to the message. Repeat the option once per file; the message then becomes multipart/mixed with the body as its first part.

$ sendsmtp smtp.example.com me@example.com you@example.com \
    -s "Nightly report" -m "See attached." -a report.pdf -a data.csv

The content type is guessed from the file name, falling back to application/octet-stream. A missing path is reported before the SMTP connection is opened, so nothing is sent and no password is asked for.

-v, --verbose

Print the SMTP dialog to stderr, report the connection and authentication steps, list the addresses the message was delivered to, and, on failure, let the full stacktrace through instead of a one-line error.

$ sendsmtp smtp.example.com me@example.com you@example.com -m "hi" -v
Connected to smtp.example.com:25 (plain).
send: 'ehlo host.example.com\r\n'
reply: b'250 smtp.example.com\r\n'
...
Message successfully sent to you@example.com

-h, --help

Print the usage summary and exit.