GNU Mailutils Manual (split by node):   Section:   Chapter:FastBack: Mailbox   Up: Mailbox   FastForward: Programs   Contents: Table of ContentsIndex: Function Index

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:


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:


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):


Expands to the sender email address.


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