1 .TH SLOCAL %manext1% "November 23, 2012" "%nmhversion%"
6 slocal \- asynchronously filter and deliver new mail
21 .\" \%[\-home\ homedir]
26 .RB [ \-verbose " | " \-noverbose ]
27 .RB [ \-suppressdup " | " \-nosuppressdup ]
34 is a program designed to allow you to have your inbound
35 mail processed according to a complex set of selection criteria.
36 You do not normally invoke
40 is invoked on your behalf by your system's Message Transfer Agent
43 when the message arrives.
45 The message selection criteria used by
46 .B slocal is specified
48 .RI \*(lq \&.maildelivery \*(rq
49 in the user's home directory.
50 You can specify an alternate file with the
53 option. The syntax of this file is specified below.
55 The message delivery address and message sender are determined from
56 the Message Transfer Agent envelope information, if possible.
59 the sender will obtained from the UUCP
60 \*(lqFrom:\*(rq line, if present. The user may override these
67 The message is normally read from the standard input. The
69 switch sets the name of the file from which the message should be
70 read, instead of reading stdin. This is useful when debugging a
71 .RI \*(lq \&.maildelivery \*(rq
78 the name of the user for
79 whom it is delivering mail. The
83 the name of the user's maildrop file.
86 is able to detect and suppress duplicate messages.
87 To enable this, use the option
91 keep a database containing the Message-ID's of incoming messages,
92 in order to detect duplicates. Depending on your configuration,
93 this database will be in either ndbm or Berkeley db format.
97 switch may be used to pass an arbitrary argument to
100 may invoke on your behalf.
106 to give information on
107 stdout about its progress. The
110 verbose debugging output on stderr. These flags are useful when
111 creating and debugging your
112 .RI \*(lq \&.maildelivery \*(rq
114 allow you to see the decisions and actions that
116 is taking, as well as check for syntax errors in your
117 .RI \*(lq \&.maildelivery \*(rq
119 .SS "Message Transfer Agents"
120 Most modern MTAs including
125 support a \&.forward file for directing incoming mail.
126 You should include the line
129 \*(lq|\ %libdir%/slocal\ \-user\ username\*(rq
131 in your \&.forward file in your home directory. This will cause
134 on your behalf when a message arrives.
135 .SS "The Maildelivery File"
137 .RI \*(lq \&.maildelivery \*(rq
141 incoming mail. Each line of this file consists of five fields, separated
142 by white-space or comma. Since double-quotes are honored, these
143 characters may be included in a single argument by enclosing the entire
144 argument in double-quotes. A double-quote can be included by preceding it
145 with a backslash. Lines beginning with `#' and blank lines are ignored.
147 The format of each line in the
148 .RI \*(lq \&.maildelivery \*(rq
152 .B "header pattern action result string"
157 The name of a header field (such as To, Cc, or From) that is to
158 be searched for a pattern. This is any field in the headers of
159 the message that might be present.
161 The following special fields are also defined:
164 the out-of-band sender information
167 the address that was used to cause delivery to the recipient
172 if the message hasn't been delivered yet
180 The sequence of characters to match in the specified header field.
181 Matching is case-insensitive, but does not use regular expressions.
186 The action to take to deliver the message. When a message is delivered,
187 a \*(lqDelivery\-Date:\ date\*(rq header is added which indicates the date
188 and time that message was delivered.
191 This action always succeeds.
193 .IR file ", " mbox ", or " >
194 Append the message to the file named by
197 appended to the file in mbox (uucp) format. This is the format used by most
198 other mail clients (such as mailx, elm). If the message can be appended to
199 the file, then this action succeeds.
204 but always appends the message using the MMDF mailbox format.
207 Pipe the message as the standard input to the command named by
209 using the Bourne shell
211 to interpret the string.
212 Prior to giving the string to the shell, it is expanded with the following
215 .TP \w'zzreplyztozaaa'u
217 the out-of-band sender information
218 .TP \w'zzreplyztozaaa'u
220 the address that was used to cause delivery to the recipient
221 .TP \w'zzreplyztozaaa'u
223 the size of the message in bytes
224 .TP \w'zzreplyztozaaa'u
226 either the \*(lqReply\-To:\*(rq or \*(lqFrom:\*(rq field of the message
227 .TP \w'zzreplyztozaaa'u
229 the out-of-band information specified
235 but executes the command
236 directly, after built-in variable expansion, without assistance from
237 the shell. This action can be used to avoid quoting special characters
238 which your shell might interpret.
241 Store the message in the
245 Currently this is handled by piping the message to the
249 although this may change in the future.
254 Indicates how the action should be performed:
257 Perform the action. If the action succeeds, then the message
258 is considered delivered.
261 Perform the action. Regardless of the outcome of the action,
262 the message is not considered delivered.
265 Perform the action only if the message has not been delivered.
266 If the action succeeds, then the message is considered delivered.
269 Perform the action only if the message has not been delivered
270 and the previous action succeeded. If this action succeeds, then the
271 message is considered delivered.
273 The delivery file is always read completely, so that several matches
274 can be made and several actions can be taken.
276 .SS "Security of Delivery Files"
277 In order to prevent security problems, the
278 .RI \*(lq \&.maildelivery \*(rq
279 file must be owned either by the user or by root, and must be
280 writable only by the owner. If this is not the case, the file is
284 .RI \*(lq \&.maildelivery \*(rq
285 file cannot be found, or does not
286 perform an action which delivers the message, then
288 will check for a global delivery file at
289 .IR %etcdir%/maildelivery .
290 This file is read according to the same rules. This file must be
291 owned by root and must be writable only by root.
293 If a global delivery file cannot be found or does not perform an
294 action which delivers the message, then standard delivery to the
295 user's maildrop is performed.
296 .SS "Example Delivery File"
297 To summarize, here's an example delivery file:
300 .ta \w'default 'u +\w'mh-workersxx 'uC +\w'destroy 'uC +\w'result 'u
302 # .maildelivery file for nmh's slocal
304 # Blank lines and lines beginning with a '#' are ignored
306 # FIELD PATTERN ACTION RESULT STRING
309 # File mail with foobar in the \*(lqTo:\*(rq line into file foobar.log
310 To foobar file A foobar.log
312 # Pipe messages from coleman to the program message-archive
313 From coleman pipe A /bin/message-archive
315 # Anything to the \*(lqnmh-workers\*(rq mailing list is put in
316 # its own folder, if not filed already
317 To nmh-workers folder ? nmh-workers
319 # Anything with Unix in the subject is put into
321 Subject unix file A unix-mail
323 # I don't want to read mail from Steve, so destroy it
324 From steve destroy A \-
326 # Put anything not matched yet into mailbox
327 default \- file ? mailbox
330 * \- pipe R %libdir%/rcvtty
332 .SS "Sub-process environment"
333 When a process is invoked, its environment is: the user/group-ids are
334 set to recipient's ids; the working directory is the recipient's home
335 directory; the umask is 0077; the process has no /dev/tty; the standard
336 input is set to the message; the standard output and diagnostic output are
337 set to /dev/null; all other file-descriptors are closed; the environment
342 are set appropriately, and no other environment variables exist.
344 The process is given a certain amount of time to execute. If the process
345 does not exit within this limit, the process will be terminated with
346 extreme prejudice. The amount of time is calculated as ((size / 60) +
347 300) seconds, where size is the number of bytes in the message (with
348 30 minutes the maximum time allowed).
350 The exit status of the process is consulted in determining the success
351 of the action. An exit status of zero means that the action succeeded.
352 Any other exit status (or abnormal termination) means that the action
355 In order to avoid any time limitations, you might implement a process
358 The parent would return the appropriate
359 value immediately, and the child could continue on, doing whatever it
360 wanted for as long as it wanted. This approach is somewhat risky if
361 the parent is going to return an exit status of zero. If the parent is
362 going to return a non-zero exit status, then this approach can lead to
363 quicker delivery into your maildrop.
367 .ta \w'%etcdir%/ExtraBigFileName 'u
368 ^%etcdir%/mts.conf~^nmh mts configuration file
369 ^$HOME/\&.maildelivery~^The file controlling local delivery
370 ^%etcdir%/maildelivery~^Rather than the standard file
371 ^%mailspool%/$USER~^The default maildrop
382 .RB ` \-nosuppressdup '
383 .RB ` \-maildelivery "' defaults to $HOME/\&.maildelivery"
384 .RB ` \-mailbox "' deaults to %mailspool%/$USER"
385 .RB ` \-file "' defaults to stdin"
386 .RB ` \-user "' defaults to the current user"
392 was originally designed to be backward-compatible with
398 .RI \*(lq \&.maildelivery \*(rq
399 file syntax is somewhat limited. But
401 has been modified and extended, so that is it no longer compatible with
404 In addition to an exit status of zero, the
410 (9) mean that the message has been fully delivered.
411 Any other non-zero exit status, including abnormal termination, is
417 \*(lquse an alternate route\*(rq (deliver the message to the maildrop).
419 Only two return codes are meaningful, others should be.
422 was originally designed to be backwards-compatible with the
424 functionality provided by