V8/usr/man/man7/mail.7

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.TH MAIL 7
.SH NAME
mail \- address conventions and rewrite rules
.SH DESCRIPTION
.IR Mail (1)
accepts and converts among the addressing conventions of
several computer networks, according to rules given in
the file
/usr/lib/upas/rewrite.
Each line of the file is a rule.
Blank lines and lines beginning with \'#\' 
are ignored.
.PP
Each rewriting rule consists of (up to) 6 strings:
.TP
.I pattern
An
.IR ed (1)-like
regular expression, with simple parentheses () playing the role
of \e(\e) and with the + and ? operators of
.IR egrep (1).
The
.I pattern
is applied to mail addresses.
.TP
.I command
An
.IR ed (1)
style replacement string to generate a
command to deliver messages to the destination matched by the
.I pattern.
The substring
.I `\|\es',
is replaced by the login id of the
sender.
The default is no command.
.TP
.I "next hop"
An
.IR ed (1)
style replacement string that represents the name of
next routing hop.
The default is the empty string.
See the section below on forwarding.
.TP
.I "next address"
An
.IR ed (1)
style replacement string that represents the address
as it will be seen at the next hop.
The default is the empty string.
See the section below on forwarding.
.TP
.I conversion
The name of the conversion that must be performed
before the message is piped to the 
.I command.
If this field is empty, no conversion
is performed.
The only conversion now known is
.I rfc822,
which makes the message conform to the
ARPA RFC 822 mailer standard.
.TP
.I system
The name to use for the current system.
The default name is found in
.I /etc/whoami.
.PP
Each field, except for
.I pattern,
is optional if it and all fields following it
are to assume the default values.
Any empty field (e.g. ``'') assumes the default value.
.PP
When delivering a message,
.I mail
starts with the first rule and continues down the list until a pattern
matches the destination address.
If the rule contains no command, the mail is appended to the user's
mailbox in the standard way (see
.IR mail (1)).
If the rule does contain a command, 
.IR upas (8)
starts the command and pipes the message to it,
performing any requested conversion.
.PP
Forwarding is controlled using the
.I "next hop"
and
.I "next address"
fields and the forwarding files.
Using these fields, the rewriting rules are recursively applied to 
the source and destination addresses.
If all hops in either source or destination are in the forwarding files,
forwarding is allowed.
If the forwarding files do not exist, blanket forwarding is assumed.
.SH EXAMPLES
.ta 2m 4m
Rewriting rules for major networks are:
.PP
network: UUCP (machine!machine!...!person)
.IP
^([^!]+)!([^!]+)$  \\1 \\
.br
	"uux 2>>/tmp/uuxl \- \-a \\s \\1!rmail \\\\(\\2\\\\)"
.br
^([^!]+)!((.+!)?([^!]+)![^!]+)$ \\4 "uux \- \-a \\s \\1!rmail \\\\(\\2\\\\)"
.PP
network: ARPANET (arpa!person@machine)
.IP
^arpa!(.+)$ csnet "cs-inject \\1.csnet-relay" rfc822
.PP
network: CSNET (csnet!person@machine)
.IP
^csnet!(.+)$ csnet "cs-inject \\1.csnet-relay" rfc822
.PP
network: CSNET or ARPANET (person@machine)
.IP
^.+[@%.][^@%.]+$ csnet "cs-inject &.csnet-relay" rfc822
.PP
network: ACSNET (acsnet!person@machine.acsnet)
.IP
^acsnet!(.+)$ ACSnet "acs-inject \\1" rfc822
.PP
network: BITNET (bitnet!person@machine)
.IP
^bitnet!(.+)[.@](.+)$ csnet
.br
	"cs-inject \\1%\\2.bitnet@wiscvm.arpa.csnet-relay" rfc822
.PP
The address on incoming mail depends largely on 
the originating mail program.
However, the following can usually be relied upon
to reach CS researchers at Bell Labs.
.PP
UUCP:  research!person
.PP
CSNET:  person@btl or person.machine@btl
.PP
ARPANET:  person@btl.csnet or person.btl@csnet-relay
.PP
ACSNET:  person@research or research!person
.PP
BITNET: person%btl.csnet@wiscvm
.PP
If in any of the above addresses, `person' is not on research, use
`machine!...!person' in place of `person'.
.SH FILES
.ta \w'/usr/lib/upas/rewrite 'u
/usr/lib/upas/rewrite	the rewriting rules
.SH "SEE ALSO"
uucp(1), mail(1), upas(8)