SLOCAL(1)

NAME
slocal - special local mail delivery

SYNOPSIS
/usr/local/lib/mh/slocal [address info sender]
[-addr address] [-info data] [-sender sender]
[-user username] [-mailbox mbox] [-file file]
[-maildelivery deliveryfile] [-verbose] [-noverbose] [-debug] [-help]

DESCRIPTION
Slocal is a program designed to allow you to have your inbound mail processed according to a complex set of selection criteria. You do not normally invoke slocal yourself, rather slocal is invoked on your behalf by your system's Message Transfer Agent. The message selection criteria used by slocal is specified in the file .maildelivery in the user's home directory. The format of this file is given below. The message delivery address and message sender are determined from the Message Transfer Agent envelope information, if possible. Under SendMail, the sender will obtained from the UUCP "From " line, if present. The user may override these values with command line arguments, or arguments to the `-addr' and `-sender' switches. The message is normally read from the standard input. The `-file' switch sets the name of the file from which the message should be read, instead of reading stdin. The `-user' switch tells slocal the name of the user for whom it is delivering mail. The `-mailbox' switch tells slocal the name of the user's maildrop file. The `-info' switch may be used to pass an arbitrary argument to sub-processes which slocal may invoke on your behalf. The `-verbose' switch causes slocal to give information on stdout about its progress. The `-debug' switch produces more verbose debugging output on stderr. If your MTA is SendMail, you should include the line

    "| /usr/local/lib/mh/slocal -user username"

in your .forward file in your home directory. This will cause SendMail to invoke slocal on your behalf. If your MTA is MMDF-I, you should (symbolically) link /usr/local/lib/mh/slocal to the file bin/rcvmail in your home directory. This will cause MMDF-I to invoke slocal on your behalf with the correct "address info sender" arguments. If your MTA is MMDF-II, then you should not use slocal. An equivalent functionality is already provided by MMDF-II; see maildelivery(5) for details. The .maildelivery file controls how local delivery is performed. Each line of this file consists of five fields, separated by white-space or comma. Since double-quotes are honored, these characters may be included in a single argument by enclosing the entire argument in double-quotes. A double-quote can be included by preceding it with a backslash. Lines beginning with `#' are ignored. The format of each line in the .maildelivery file is:
    header    pattern    action    result    string

header:
The name of a header field that is to be searched for a pattern. This is any field in the headers of the message that might be present. The following special fields are also defined:

source    the out-of-band sender information
addr    the address that was used to cause delivery to the recipient
default    this matches only if the message hasn't been delivered yet
*    this always matches
pattern:
The sequence of characters to match in the specified header field. Matching is case-insensitive, but does not use regular expressions.
action:
The action to take to deliver the message:

destroy    This action always succeeds.
file or >    Append
the message to the file named by string. The message is appended to the file in the maildrop format which is used by your message transport system. If the message can be appended to the file, then this action succeeds. When writing to the file, a "Delivery-Date: date" header is added which indicates the date and time that message was appended to the file.
mbox    Identical
to file, but always appends the message using the format used by packf (the MMDF mailbox format).
pipe or |    Pipe
the message as the standard input to the command named by string, using the Bourne shell sh(1) to interpret the string. Prior to giving the string to the shell, it is expanded with the following built-in variables:

$(sender)     the out-of-band sender information
$(address)     the address that was used to cause delivery to the recipient
$(size)    the size of the message in bytes
$(reply-to)     either the "Reply-To:" or "From:" field
of the message
$(info)    the out-of-band information specified
qpipe or
<caret>    Similar to pipe,
but executes the command directly, after built-in variable expansion, without assistance from the shell. This action can be used to avoid quoting special characters which your shell might interpret.
result:
Indicates how the action should be performed:
A    Perform the action.
If the action succeeds, then the message is considered delivered.
R    Perform the action.
Regardless of the outcome of the action, the message is not considered delivered.
?    Perform
the action only if the message has not been delivered. If the action succeeds, then the message is considered delivered.
N    Perform
the action only if the message has not been delivered and the previous action succeeded. If this action succeeds, then the message is considered delivered.

To summarize, here's an example:

#field	pattern	action	result	string
# lines starting with a '#' are ignored, as are blank lines
#
# file mail with mmdf2 in the "To:" line into file mmdf2.log
To	mmdf2	file	A	mmdf2.log
# Messages from mmdf pipe to the program err-message-archive
From	mmdf	pipe	A	/bin/err-message-archive
# Anything with the "Sender:" address "mh-workers"
# file in mh.log if not filed already
Sender	mh-workers	file	?	mh.log
# "To:" unix - put in file unix-news
To	Unix	>	A	unix-news
# if the address is jpo=ack - send an acknowledgement copy back
addr	jpo=ack	|	R	"/bin/resend -r $(reply-to)"
# anything from steve - destroy!
From	steve	destroy	A	-
# anything not matched yet - put into mailbox
default	-	>	?	mailbox
# always run rcvtty
*	-	|	R	/mh/lib/rcvtty
The file is always read completely, so that several matches can be made and several actions can be taken. The .maildelivery file must be owned either by the user or by root, and must be writable only by the owner. If the .maildelivery file cannot be found, or does not perform an action which delivers the message, then the file /usr/local/lib/mh/maildelivery is read according to the same rules. This file must be owned by the root and must be writable only by the root. If this file cannot be found or does not perform an action which delivers the message, then standard delivery to the user's maildrop is performed. When a process is invoked, its environment is: the user/group-ids are set to recipient's ids; the working directory is the recipient's home directory; the umask is 0077; the process has no /dev/tty; the standard input is set to the message; the standard output and diagnostic output are set to /dev/null; all other file-descriptors are closed; the envariables $USER, $HOME, $SHELL are set appropriately, and no other envariables exist. The process is given a certain amount of time to execute. If the process does not exit within this limit, the process will be terminated with extreme prejudice. The amount of time is calculated as ((size x 60) + 300) seconds, where size is the number of bytes in the message. The exit status of the process is consulted in determining the success of the action. An exit status of zero means that the action succeeded. Any other exit status (or abnormal termination) means that the action failed. In order to avoid any time limitations, you might implement a process that began by forking. The parent would return the appropriate value immediately, and the child could continue on, doing whatever it wanted for as long as it wanted. This approach is somewhat risky if the parent is going to return an exit status of zero. If the parent is going to return a non-zero exit status, then this approach can lead to quicker delivery into your maildrop.
/usr/local/lib/mh/mtstailor    MH tailor file
$HOME/.maildelivery    The file controlling local delivery
/usr/local/lib/mh/maildelivery    Rather than the standard file
/var/mail/$USER    The default maildrop
rcvstore(1), mhook(1), mh-format(5) `-noverbose' `-maildelivery .maildelivery' `-mailbox /var/mail/$USER' `-file' defaults to stdin `-user' defaults to the current user None Slocal is designed to be backward-compatible with the maildelivery facility provided by MMDF-II. Thus, the .maildelivery file syntax is limited, as is the functionality of slocal. In addition to an exit status of zero, the MMDF values RP_MOK (32) and RP_OK (9) mean that the message has been fully delivered. Any other non-zero exit status, including abnormal termination, is interpreted as the MMDF value RP_MECH (200), which means "use an alternate route" (deliver the message to the maildrop). Only two return codes are meaningful, others should be. Slocal is designed to be backwards-compatible with the maildelivery functionality provided by MMDF-II. Versions of MMDF with the maildelivery mechanism aren't entirely backwards-compatible with earlier versions of MMDF. If you have an MMDF-I old-style hook, the best you can do is to have a one-line .maildelivery file:
default - pipe A "bin/rcvmail $(address) $(info) $(sender)"