msmtp

lightweight SMTP client for sending email from the command line

TLDR

Send email

$ echo "[message]" | msmtp [recipient@example.com]

Send email with subject

$ echo -e "Subject: [Hello]\n\n[Body]" | msmtp [recipient@example.com]

Send from specific account

$ msmtp -a [account_name] [recipient@example.com]

Test configuration

$ msmtp --serverinfo

Check account configuration

$ msmtp --configure [account_name]

Send file as message

$ msmtp [recipient@example.com] < [message.txt]

Print configuration

$ msmtp -P

SYNOPSIS

msmtp [-a account] [--serverinfo] [options] [recipients]

msmtp is a lightweight SMTP client for sending email from the command line. It works as a sendmail replacement, enabling scripts and applications to send mail through external SMTP servers.
Configuration in ~/.msmtprc defines accounts with server settings, authentication, and TLS options. Multiple accounts can be configured for different mail servers or identities.
Password handling supports several methods: plaintext (not recommended), passwordeval to run a command (e.g., password manager), or system keyring integration.
TLS is supported via STARTTLS or direct TLS connection. Certificate verification can be configured to use system CA certificates or specific files.
As a sendmail replacement, msmtp can be symlinked to /usr/sbin/sendmail, making it the default mail transport for the system. Many applications use sendmail for outgoing mail.
Integration with mutt, git, and other tools is straightforward - they just need to know the sendmail path or can use msmtp directly.

PARAMETERS

-a ACCOUNT, --account ACCOUNT

Use specified account.

-f ADDRESS, --from ADDRESS

Set From address.

-C FILE, --file FILE

Use configuration file.

--serverinfo

Print server information.

-P, --pretend

Print configuration, don't send.

--configure ACCOUNT

Show account configuration.

-d, --debug

Debug mode.

-t, --read-recipients

Read recipients from message.

-X FILE, --logfile FILE

Log to file.

--tls

Use TLS encryption.

--tls-starttls

Use STARTTLS.

--host HOST

SMTP server host.

--port PORT

SMTP server port.

--user USER

Authentication username.

--passwordeval CMD

Get password from command.

CAVEATS

Requires SMTP server access. Password storage needs consideration. Some providers require app-specific passwords. TLS certificate issues may occur. Queue/offline sending requires msmtpd or msmtp-queue.

HISTORY

msmtp was written by Martin Lambers starting around 2000 as a simple sendmail replacement. It focused on being lightweight and configurable, supporting modern SMTP with authentication and TLS. The project remains actively maintained.