2.4 Program Mailboxes

Program mailboxes support only append operation. Appending a message is performed by invoking the specified program and passing the message to its standard input stream.

A ‘sendmail’ mailbox is identified by the following URL:

sendmail[://path]

The messages are sent by invoking sendmail binary with the -oi -t options. If the message being appended has the ‘From:’ header, its value is passed to sendmail using the -f option.

The default path to the sendmail binary is system-dependent. The path part can be used to specify it explicitly.

The ‘prog’ mailbox URL is:

prog://pathname[?query]

Messages are appended by invoking the program pathname with the arguments supplied by query. The latter is a list of words delimited by ‘&’ characters.

Arguments can contain the following variables (see Variables):

sender

Expands to the sender email address.

rcpt

Expands to comma-separated list of email addresses obtained from ‘To:’, ‘Cc:’ and ‘Bcc:’ headers of the message.