calibre-smtp(1) part of calibre


calibre-smtp [options] [from to text]


Send mail using the SMTP protocol. calibre-smtp has two modes of operation. In the compose mode you specify from to and text and these are used to build and send an email message. In the filter mode, calibre-smtp reads a complete email message from STDIN and sends it.

text is the body of the email message. If text is not specified, a complete email message is read from STDIN. from is the email address of the sender and to is the email address of the recipient. When a complete email is read from STDIN, from and to are only used in the SMTP negotiation, the message headers are not modified.

Whenever you pass arguments to calibre-smtp that have spaces in them, enclose the arguments in quotation marks.


show program's version number and exit
-h, --help
show this help message and exit
-l, --localhost
Host name of localhost. Used when connecting to SMTP server.
-o, --outbox
Path to maildir folder to store failed email messages in.
-f, --fork
Fork and deliver message in background. If you use this option, you should also use --outbox to handle delivery failures.
-t, --timeout
Timeout for connection
-v, --verbose
Be more verbose


Options to compose an email. Ignored if text is not specified

-a, --attachment
File to attach to the email
-s, --subject
Subject of the email


Options to use an SMTP relay server to send mail. calibre will try to send the email directly unless --relay is specified.

-r, --relay
An SMTP relay server to use to send mail.
Port to connect to on relay server. Default is to use 465 if encryption method is SSL and 25 otherwise.
-u, --username
Username for relay
-p, --password
Password for relay
-e, --encryption-method
Encryption method to use when connecting to relay. Choices are TLS, SSL and NONE. Default is TLS. WARNING: Choosing NONE is highly insecure