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+.TH MAIL 1
+.SH NAME
+mail, marshal, nedmail, send, aliasmail, smtp, smtpd, vwhois, filter, fs, biff, pop3, ml, mlmgr, mlowner, list, deliver, token, vf \-  mail commands
+.SH SYNOPSIS
+.B mail
+[
+.I arg ...
+]
+.PP
+.B upas/marshal
+[
+.B -t
+.I mime-type
+]
+[
+.B -[aA]
+.I attachment
+]
+[
+.B -s
+.I subject
+]
+[
+.B -r
+]
+[
+.B -x
+]
+[
+.B -#
+]
+[
+.B -n
+]
+[
+.I mailaddr ...
+]
+.PP
+.B upas/send
+[
+.B -b
+]
+[
+.B -i
+]
+[
+.B -r
+]
+[
+.B -x
+]
+[
+.B -#
+]
+[
+.B -n
+]
+[
+.I mailaddr ...
+]
+.PP
+.B upas/nedmail
+[
+.B -c [dir]
+]
+[
+.B -r
+]
+[
+.B -n
+]
+[
+.B -f
+.I mailfile
+]
+[
+.B -s
+.I mailfile
+]
+.PP
+.B upas/fs
+[
+.B -f
+.I mailbox
+]
+[
+.B -b
+]
+[
+.B -n
+]
+[
+.B -p
+]
+.PP
+.B upas/biff
+.PP
+.B upas/filter
+[
+.B -bh
+]
+.I rcvr
+.I mailbox
+.I "regexp file
+[
+.I "regexp file
+]*
+.PP
+.B upas/list add|check
+.I patterns
+.I addrfile ...
+.PP
+.B upas/deliver 
+.I recipient
+.I fromfile
+.I mbox
+.PP
+.B upas/token
+.I key
+[
+.I tokenfile
+]
+.PP
+.B upas/pop3
+.PP
+.B upas/mlmgr -c
+.I listname
+.PP
+.B upas/mlmgr -ar
+.I listname
+.I address
+.PP
+.B upas/ml
+.I addressfile
+.I listname
+.PP
+.B upas/mlowner
+.I addressfile
+.I listname
+.PP
+upas/vf
+.SH DESCRIPTION
+.SS Mail
+Mail is a shell script that invokes
+.I upas/nedmail
+when no  recipients appear on the command line and
+.I upas/marshal
+otherwise.
+All command line options are passed through.
+.SS "Sending mail
+.I Marshal
+builds a mail message from standard input and passes it
+for transmission or delivery to
+.B /bin/myupassend
+if it exists, otherwise to
+.BR /bin/upas/send .
+The message format is both RFC 822 and
+MIME conformant, so
+.I marshal
+adds any required headers not already in the message.
+Before adding any necessary header lines, it prepends
+the contents of
+.BI /mail/box/ username /headers\f1.
+This allows the addition of personal headers like
+.B From:
+lines with a full name or a different
+return address.
+Command line options direct marshal to add a subject line
+and append attachments.  The arguments to
+.I marshal
+are the addresses of the recipients.
+.PP
+When running in a
+.IR rio (1)
+window,
+.I marshal
+automatically puts the window into hold mode (see
+.IR rio (1));
+this means that the message can be edited freely,
+because nothing will be sent to
+.I marshal
+until the ESC key is hit to exit hold mode.
+.PP
+The options are:
+.TF "-a file"
+.TP
+.BI -a file
+directs
+.I marshal
+to append 
+.I file
+as a mime attachment.
+Unless explicitly specified by the
+.B -t
+option, the type of the attachment is determined
+by running the
+.IR file (1)
+command.
+.TP
+.BI -A file
+is like
+.B -a
+but the message disposition is marked as
+.I inline
+directing any mail reader to display the attachment
+(if it can) when the mail message is read.
+.TP
+.BI -t type
+sets the content type for the attachments from
+all subsequent
+.B -a
+and
+.B -A
+options.
+.TP
+.BI -s subject
+adds a
+.B Subject:
+header line to the message if one does not
+already exist.
+.TP
+.B -#xnr
+are all passed as command line options to the
+.I send
+that
+.I marshal
+invokes.
+.PD
+.PP
+.I Send
+reads a message from standard input and disposes of it in one
+of four ways:
+.IP \(bu 3
+If
+.I mailaddr
+refers to a local mailbox, it appends it to the
+recipient's mailbox.
+.IP \(bu
+If
+.I mailaddr
+is remote, it queues the mail for remote delivery.
+.IP \(bu
+If the
+.B -r
+option is given and the mail is undeliverable, it
+returns the mail to the sender.
+.IP \(bu
+if the
+.B -r
+option is not given and the mail is undeliverable, it
+appends the mail to
+.BI /mail/box/ username /dead.letter
+and prints a message to standard error.
+.PP
+The file
+.B /mail/lib/rewrite
+determines exactly how to deliver or queue the mail.
+The decision is based purely on the recipient address.
+.PP
+The options are:
+.TF -b
+.TP
+.B -b
+suppresses the addition of the
+.B To:
+line.
+.TP
+.B -i
+let the message input be terminated by a line
+containing only a period, for
+compatibility with
+old mailers.
+.TP
+.B -x
+do not send mail, but instead report
+the full mail address of the recipient.
+.TP
+.B -#
+do not send mail, but instead report
+what command would be used to send the mail.
+.TP
+.B -r
+input is via a pipe from another program.
+Expect a From
+line at the start of the message to provide the
+name of the sender and timestamp.  This implies
+the
+.B -b
+option.
+.SS "Reading mail"
+.I Nedmail
+edits a mailbox.
+The default mailbox is
+.BI /mail/box/ username /mbox\f1.
+The
+.B -f
+command line option specifies an alternate mailbox.
+Unrooted path names are interpreted relative to
+.BI /mail/box/ username.
+If the
+.I mailfile
+argument is omitted, the name defaults to
+.BR stored .
+.PP
+The options are:
+.TF "-f mailfile"
+.TP
+.BI -c " dir
+Create a mailbox.  If
+.I dir
+is specified, the new mailbox is created in
+.BI /mail/box/ username / dir /mbox\f1.
+Otherwise, the default mailbox is created.
+.TP
+.B -r
+Reverse: show messages in first-in, first-out order; the default is last-in, first-out.
+.TP
+.B -n
+Make the message numbers the same as the file names in the mail
+box directory.  This implies the
+.B -r
+option.
+.TP
+.BI -f " mailfile"
+Read messages from the specified file (see above) instead of the default mailbox.
+.TP
+.BI -s " mailfile"
+Read a single message file
+.IR mailfile ,
+as produced by
+.IR fs ,
+and treat it as an entire mailbox.
+This is provided for
+use in plumbing rules; see
+.IR faces (1).
+.PD
+.PP
+.I Nedmail
+starts by reading the mail box, printing out the number
+of messages, and then prompting for commands from standard input.
+Commands, as in
+.IR ed (1),
+are of the form
+.RI `[ range ]
+.I command
+.RI [ arguments ]'.
+The command is applied to each message in the (optional) range.
+.PP
+The address range can be:
+.TP 1.4i
+.I address
+to indicate a single message header
+.PD 0
+.TP
+.IB address , address
+to indicate a range of contiguous message headers
+.TP
+.BI g/ expression /
+to indicate all messages whose headers match the regular
+.IR expression .
+.TP
+.BI g% expression %
+to indicate all messages whose contents match the regular
+.IR expression .
+.PD
+.PP
+The addresses can be:
+.TP 1.4i
+.I number
+to indicate a particular message
+.PD 0
+.TP
+.IB address . number
+to indicate a subpart of a particular message
+.TP
+.BI / expression /
+to indicate the next message whose header matches
+.I expression
+.TP
+.BI % expression %
+to indicate the next message whose contents match
+expression
+.TP
+.I "empty or .
+to indicate the current message
+.TP
+.BI - address
+to indicate backwards search or movement
+.PD
+.PP
+Since messages in MIME are hierarchical
+structures, in
+.I nedmail
+all the subparts are individually addressable.
+For example if message 2 contains 3 attachments,
+the attachments are numbered 2.1, 2.2, and 2.3.
+.PP
+The commands are:
+.TP 1.1i
+.BI a " args
+Reply to all addresses in the
+.BR To: ,
+.BR From: ,
+and
+.BR Cc:
+header lines.
+.I Marshal
+is used to format the reply and any arguments the
+user specifies are added to the command line to
+.I marshal
+before the recipient.
+The possibility of making a fool of yourself is very
+high with this command.
+.PD 0
+.TP
+.BI A " args
+Like 
+.B a
+but with the message
+appended to the reply.
+.TP
+.B b
+Print the headers for the next ten messages.
+.TP
+.B d
+Mark message to be deleted upon exiting
+.IR nedmail .
+.TP
+.B f
+Append the message to the file 
+.BI /mail/box/ username / sendername
+where
+.I sendername
+is the account name of the sender.
+.TP
+.B h
+Print the disposition, size in characters, reception time, sender,
+and subject of the message.
+.TP
+.B H
+Print the MIME structure of the message.
+.TP
+.B help
+Print a summary of the commands.
+.TP
+.BI m " person ...
+Forward the message as a mime attachment to the named
+.IR persons .
+.TP
+.BI M " person ...
+Like
+.B m
+but allow the user to type in text to be included
+with the forwarded message.
+.TP
+.B p
+Print message.	An interrupt stops the printing.
+.TP
+.BI r " args
+Reply to the sender of the message.
+.I Marshal
+is used to format the reply.
+If and optional
+.I Args
+are specified, they are added to the command line to
+.I marshal
+before the recipient's address.
+.TP
+.B R " args 
+Like
+.B r
+but with the original message included as an attachment.
+.TP
+.B rf
+Like
+.B r
+but append the message and the reply to the file 
+.BI /mail/box/ username / sendername
+where
+.I sendername
+is the account name of the sender.
+.TP
+.B Rf
+Like 
+.B R
+but append the message and the reply to the file 
+.BI /mail/box/ username / sendername
+where
+.I sendername
+is the account name of the sender.
+.TP
+.BI s " mfile"
+Append the message to the specified mailbox.
+If
+.I mfile
+doesn't start with a `/', it is interpreted relative to the directory in which the mailbox resides.
+.TP
+.B q
+Put undeleted mail back in the mailbox and stop.
+.TP
+EOT (control-D)
+Same as 
+.BR q .
+.TP
+.BI w " file
+Same as
+.B s
+with the mail header line(s) stripped.  This can be used to
+save binary mail bodies.
+.TP
+.B u
+Remove mark for deletion.
+.TP
+.B x
+Exit, without changing the mailbox file.
+.TP
+.BI | command
+Run the
+.I command
+with the message as standard input.
+.TP
+.BI ! command
+Escape to the shell to do
+.IR command .
+.TP
+.B \&=
+Print the number of the current message.
+.PD
+.PP
+Here's an example of a mail session that looks at a summary
+of the mail messages, saves away an html file added as an
+attachment to a message and then deletes the message:
+.LP
+.EX
+% mail
+7 messages
+: ,h
+1   H  2129	07/22 12:30  noone@madeup.net  "Add Up To 2000 free miles"
+2       504	07/22 11:43  jmk
+3   H   784	07/20 09:05  presotto
+4       822	07/11 09:23  xxx@yyy.net  "You don't call, you don't write..."
+5       193	07/06 16:55  presotto
+6       529	06/01 19:42  jmk
+7       798	09/02  2000  howard
+: 1H
+1       multipart/mixed             2129   from=noone@madeup.net
+ 1.1      text/plain                115    
+ 1.2      text/html                 1705   filename=northwest.htm
+: 1.2w /tmp/northwest.html
+!saved in /tmp/northwest.html
+1.2: d
+1: q
+!1 message deleted
+% 
+.EE
+.PP
+Notice that the delete of message 1.2 deleted the entire message and
+not just the attachment.
+.SS "Aliasmail"
+.I Aliasmail 
+expands mail aliases, its arguments, according to alias files.
+Each line of an alias file begins with
+.B #
+(comment) or with a name.
+The rest of a name line gives the expansion.
+The expansion may contain multiple addresses and may be continued
+to another line by appending a backslash.
+Items are separated by white space.
+.PP
+In expanding a name, the sender's personal alias file
+.BI /mail/box/ username /names 
+is checked first.
+Then the system alias files, listed one per line in
+.BR /mail/lib/namefiles  ,
+are checked in order.
+If the name is not found, the expansion is taken to be
+.BI local! name\f1.
+Under the
+.B -f
+option,
+alias files listed in
+.B /mail/lib/fromfiles
+are consulted instead,
+and the domain part only of the expansion is printed.
+.SS Mailboxes
+Incoming mail for a user
+.I username
+is put in the file
+.BI /mail/box/ username /mbox
+unless either the file
+.BI /mail/box/ username /forward
+or
+.BI /mail/box/ username /pipeto
+exists.
+The mailbox must have append-only and exclusive-access mode
+(see
+.IR chmod (1)).
+A user must create his or her own mailbox using the
+.B -c
+option of
+.IR nedmail .
+Mailboxes are created writable (append-only) but not readable by others.
+.SS Forwarding
+If the file
+.BI /mail/box/ username /forward
+exists and is readable by everyone, incoming mail
+will be forwarded to the addresses contained in the first line of the file.
+The file may contain multiple addresses.
+Forwarding loops are caught and resolved by local delivery.
+.SS Filtering
+If the file
+.BI /mail/box/ username /pipeto
+exists and is readable and executable by everyone,
+it will be run for each incoming message for the user.
+The message will be piped to it rather
+than appended to his/her mail box.
+The file is run as user
+.B none
+with arguments of the resolved address of
+.I username
+(e.g.,
+.BR local!presotto )
+and the user's mail box name.
+.PP
+.I Filter
+provides simple mail filtering.
+The first two arguments are the recipient's address and mailbox, that is,
+the same arguments provided to
+.BR pipeto .
+The remaining arguments are all pairs of a regular expression and a file name.
+With no flags, the sender's address is matched against each
+regular expression starting with the first.  If the expression
+matches, then the message is delivered to the file whose name
+follows the expression.  The file must be world writable and should
+be append only.
+A message that matches none of the expressions is delivered into
+the user's standard mail box.
+The flags are:
+.TP
+.B h
+the regular expression is matched against the message header
+rather than the address.
+.TP
+.B b
+the regular expression is matched against both the header and the body
+of the message.
+.PP
+For example, to delete any messages of precedence bulk, place in
+your
+.B pipeto
+file:
+.EX
+/bin/upas/filter -h $1 $2 'Precedence: bulk' /dev/null
+.EE
+.PP
+Three other commands exist which, combined by an
+.IR rc (1)
+script, allow you to build your own filter.
+.PP
+.I List
+takes two verbs;
+.B check
+and
+.BR add .
+.B Check
+directs
+.I list
+to check each address contained in the
+.IR addressfile s
+against a list of patterns in
+.IR patternfile .
+Patterns come in four forms:
+.TP
+.B ~\fIregular-expression\fP
+If any address matches the regular expression,
+.I list
+returns successfully.
+.TP
+.BR =\fIstring\fP .
+If any address exactly matches
+.IR string ,
+.I list
+returns successfully.
+.TP
+.B !~\fIregular-expression\fP
+If any address matches the regular expression
+and no other address matches a non `!' rule,
+.I list
+returns error status "!match".
+.TP
+.B !=\fIstring\fP
+If any address exactly matches
+.I string
+and no other address matches a non `!' rule,
+.I list
+returns error status "!match".
+.PP
+If no addresses match a pattern,
+.I list
+returns "no match".
+.PP
+The pattern file may also contain lines of the form
+.EX
+#include filename
+.EE
+This allows pattern files to include other pattern
+files.
+All pattern matches are case insensitive.
+.I List
+searches the pattern file (and its includes) in order.
+The first matching pattern determines the action.
+.PP
+.I List
+.B add
+directs
+.I list
+to add a pattern to
+.I patternfile
+for each address in the
+.IR addrssfile 's
+that doesh't already match a pattern.
+.PP
+.IR Token ,
+with only one argument, prints to standard output a unique token
+created from the current date and
+.IR key .
+With two arguments, it checks
+.I token
+against tokens created over the last 10 days with
+.IR key .
+If a match is found, it returns successfully.
+.PP
+.I Deliver
+delivers into mail box
+.I mbox
+the message read from standard input.
+It obeys standard mail file locking and logging
+conventions.
+.PP
+A sample 
+.B pipeto
+using the filter kit can be found in
+.BR /sys/src/cmd/upas/filterkit/pipeto.sample .
+.PP
+A sample
+.BR myupassend ,
+.BR /sys/src/cmd/upas/filterkit/myupassend.sample ,
+is provided which adds all addresses of your outgoing
+mail to your pattern file.
+You should copy it into a directory that normally gets
+bound by your profile onto
+.BR /bin .
+.SS "Mime File system
+.PP
+.I Fs
+is a user level file system that reads mailboxes and presents them as a file
+system.
+A user normally starts
+.I fs
+in his/her profile after starting
+.IR plumber (4)
+and before starting
+a window system, such as
+.IR rio (1)
+or
+.IR acme (1).
+The file system is used by
+.I nedmail
+and
+.IR acme (1)'s
+mail reader to parse messages.
+.I Fs
+also generates plumbing messages used by
+.IR biff
+and
+.IR faces (1)
+to provide mail announcements.
+.PP
+The mailbox itself becomes a directory under
+.BR /mail/fs .
+Each message in the mailbox becomes a numbered directory in the
+mailbox directory, and each attachment becomes a numbered directory
+in the message directory.  Since an attachment may itself be a mail message,
+this structure can recurse ad nauseam.
+.PP
+Each message and attachment directory contains the files:
+.TP 1.4i
+.B body
+.PD 0
+the message minus the RFC822 style headers
+.TP
+.B cc
+the address(es) from the CC: header
+.TP
+.B date
+the date in the message, or if none, the time of delivery
+.TP
+.B digest
+an SHA1 digest of the message contents
+.TP
+.B disposition
+.B inline
+or
+.B file
+.TP
+.B filename
+a name to use to file an attachment
+.TP
+.B from
+the from address in the From: header, or if none,
+the address on the envelope.
+.TP
+.B header
+the RFC822 headers
+.TP
+.B info
+described below, essentially a summary of the header info
+.TP
+.B inreplyto
+contents of the
+.B in-reply-to:
+header
+.TP
+.B mimeheader
+the mime headers
+.TP
+.B raw
+the undecoded MIME message
+.TP
+.B rawbody
+the undecoded message body
+.TP
+.B rawheader
+the undecoded message header
+.TP
+.B replyto
+the address to send any replies to.
+.TP
+.B subject
+the contents of the subject line
+.TP
+.B to
+the address(es) from the To: line.
+.TP
+.B type
+the MIME content type
+.TP
+.B unixheader
+the envelope header from the mailbox
+.PD
+.PP
+The
+.B info
+file contains the following information, one item per line.  Lists
+of addresses are single space separated.
+.IP
+.TP 2i
+.I "sender address
+.PD 0
+.TP
+.I "recipient addresses
+.TP
+.I "cc addresses
+.TP
+.I "reply address
+.TP
+.I "envelope date
+.TP
+.I "subject
+.TP
+.I "MIME content type
+.TP
+.I "MIME disposition
+.TP
+.I filename
+.TP
+.I "SHA1 digest
+.TP
+.I "bcc addresses
+.TP
+.I "in-reply-to: contents
+.TP
+.I "RFC822 date
+.TP
+.I "message senders
+.TP
+.I "message id
+.TP
+.I "number of lines in body
+.PD
+.PP
+Deleting message directories causes the message to be removed from
+the mailbox.
+.PP
+The mailbox is reread and the structure updated
+whenever the mailbox changes.  Message directories are
+not renumbered.
+.PP
+The file
+.B /mail/fs/ctl
+is used to direct
+.I fs
+to open/close new mailboxes or to delete groups of messages atomically.
+The messages that can be written to this file are:
+.TP 2i
+.PD 0
+.B "open \fIpath mboxname\fP
+opens a new mailbox.
+.I path
+is the file to open, and
+.I mboxname
+is the name that appears under
+.BR /mail/fs .
+.TP
+.B "close \fImboxname\fP
+close
+.IR mboxname .
+The close takes affect only after all files open under
+.BI /mail/fs/ mboxname
+have been closed.
+.TP
+.B "delete \fImboxname number ...\fP
+Delete the messages with the given numbers from
+.IR mboxname.
+.PD
+.PP
+The options are:
+.TF "-f file
+.TP
+.BI -f file
+use
+.I file
+as the mailbox instead of the default,
+.BI /mail/box/ username /mbox.
+.PD 0
+.TP
+.B -b
+stands for biffing.  Each time new mail
+is received, a message is printed to standard
+output containing the sender address, subject,
+and number of bytes.  It is intended for
+people telnetting in who want mail announcements.
+.TP
+.B -n
+Don't open a mailbox initially.  Overridden by -f.
+.TP
+.B -p
+turn off plumbing.  Unless this is specified,
+.I fs
+sends a message to the plumb port,
+.BR seemail ,
+from source
+.B mailfs
+for each message received or deleted.
+The message contains the attributes
+.IR sender = "<contents of from file>" ,
+.IR filetype =mail,
+.IR mailtype = "deleted or new" ,
+and
+.IR length = "<message length in bytes>" .
+The contents of the message is the full path
+name of the directory representing the message.
+.TP
+.B -s
+causes
+.I fs
+to put itself in
+.B /srv
+with a name of the form
+.BR /srv/upasfs.\fIuser\fP .
+.TP
+.B -m
+specifies a mount point other than
+.BR /mail/fs .
+.PD
+.PP
+.I Fs
+will exit once all references to its directory
+have disappeared.
+.SS "Mail Announcements
+.PP
+.I Biff
+is the textual equivalent of
+.IR faces (1).
+It listens to plumbing messages from
+.I fs
+and for each new message prints to standard output a line
+containing the sender address, subject,
+and number of bytes.
+It exists for people without graphics capability or with screens too small to
+dedicate the space
+.IR faces (1)
+requires.  It forks to place itself in the background.
+.SS "Remote delivery
+.PP
+.I Smtp
+sends the mail message from standard input
+to the users
+.I rcpt-list
+on the host at network address
+.I address 
+using the Simple Mail Transfer Protocol.
+The return address of the mail will contain the local
+system name from the environment variable
+.I sysname
+and the user
+.IR sender .
+The
+.B -h
+option uses
+.I host
+as the local system name;
+it may be fully-qualified or not.
+If
+.I .domain
+is given, it is appended to the end of the system name.
+The
+.B -f
+option just prints out the converted message rather than
+sending it to the destination.
+The
+.B -g
+option specifies a gateway system to pass the message to if smtp can't
+find an address or MX entry for the destination system.
+The
+.B -d
+option turns on debugging output to standard error.
+.PP
+.I Smtpd
+receives a message using the Simple Mail Transfer Protocol.
+Standard input and output are the protocol connection.
+.PP
+The options are:
+.TP 1.1i
+.B -d
+turns on debugging output to standard error.
+.TP
+.B -r
+turns on forward DNS validation of non-trusted sender address.
+.TP
+.B -f
+prevents relaying from non-trusted networks.
+.TP
+.B "-n \fItcp-directory\fP"
+specifies the name of the network directory assigned to the incoming connection.
+This is used to determine the peer IP address.  If this flag is not
+specified, the peer address is determined using standard input.
+.TP
+.B "-h \fIdomain\fP"
+specifies the receiving domain.  If this flag is not specified, the
+receiving domain is inferred from the host name.
+.TP
+.B -s
+causes copies of blocked messages to be saved in a sub-directory of
+.BR /mail/queue.dump .
+.TP
+.B "-k \fIIP address\fP"
+causes connections from the host at
+.I "IP address"
+to be dropped at program startup.  Multiple addresses
+can be specified with several
+.B -k
+options.  This option should be used carefully;
+it is intended to lessen the effects of denial of
+service attacks or broken mailers which continually
+connect.  The connections are not logged and the
+remote system is not notified via the protocol.
+.PP
+.I Smtpd
+is normally run by a network listener such as
+.IR listen (8).
+Most of the command line options are more conveniently
+specified in the smtpd configuration file stored in
+.BR /mail/lib/smtpd.conf .
+.SS "Mailing lists
+.I Mlmgr
+creates and updates unmoderated mailing lists.
+The
+.B \-c
+option creates mail directories for both
+.I listname
+and
+.IB listname -owner\f1,\fP
+each containing a
+.B pipeto
+file.
+Messages mailed to
+.I listname
+are sent to all members of the mailing list.
+Any
+.B Reply-to:
+and
+.B Precedence:
+fields are
+removed from the messages and new ones are added
+directing replies to
+.I listname
+and specifying bulk precedence.  The envelope address for
+error replies is set to
+.BR /dev/null .
+.PP
+The mailing list membership is the file
+.BR /mail/box/\fIlistname\fP/address-list .
+This file is an add/remove log.  Each line
+represents a single address.  Lines beginning
+with a hash
+.RB ( # )
+are comments.
+Lines beginning with an exclamation point
+.RB ( ! )
+are removals.
+All other lines are additions.
+.PP
+Addition and removal entries can be appended using the
+.B -a
+and
+.B -r
+options to
+.IR mlmgr .
+However, they are normally appended as a consequence or
+user requests.
+.PP
+To be added or removed from the list, a user
+may send a message to
+.IB listname -owner\f1.\fP
+containing a key word in
+the header or body.  The key words are:
+.IP
+subscribe - add my
+.B From:
+address to the list
+.IP
+remove - remove my
+.B From:
+address from the list
+.IP
+unsubscribe - remove my
+.B From:
+address from the list
+.PP
+Addition and removal events cause notification messages to
+be sent to the added/removed address.   In the case of
+addition, the message describes how to be removed.
+.PP
+.I Ml
+and
+.I mlowner
+are the programs that receive messages for
+.I listname
+and
+.IB listname -owner
+respectively.
+Appropriate calls to them are inserted in the
+.B pipeto
+files created by
+.IR mlmgr .
+.SS "Virus Wrapper
+.I Vf
+takes a mail message as standard input, searches for executable
+MIME attachments, wraps them in a warning message, and appends
+.B .suspect
+to any related filenames.
+.B /sys/lib/mimetype
+contains the list of known MIME content types and file extensions.
+.I Vf
+wraps all those for which the fifth field of
+.B mimetype
+is
+.BR n .
+.SS "Mail server
+.I Pop3
+is a rudimentary POP3 server that uses APOP for authentication.
+It predates
+.I upas/fs
+and does not use it.  It will soon be replaced by one that uses
+.IR upas/fs .
+See also the IMAP4 server described in
+.IR ipserv (8).
+.SH FILES
+.TF /mail/box/*/dead.letter
+.TP
+.B /sys/log/mail
+mail log file
+.TP
+.B /mail/box/*
+mail directories
+.TP
+.B /mail/box/*/mbox
+mailbox files
+.TP
+.B /mail/box/*/forward
+forwarding address(es)
+.TP
+.B /mail/box/*/pipeto
+mail filter
+.TP
+.B /mail/box/*/L.reading
+mutual exclusion lock for multiple mbox readers
+.TP
+.B /mail/box/*/L.mbox
+mutual exclusion lock for altering mbox
+.TP
+.B /mail/box/*/dead.letter
+unmailable text
+.TP
+.B /mail/box/*/names
+personal alias files
+.TP
+.B /mail/lib/rewrite
+rules for handling addresses
+.TP
+.B /mail/lib/namefiles
+lists files to search for aliases in
+.TP
+.B /lib/face/48x48x?
+directories of icons for
+.I seemail
+.SH SOURCE
+.TF /sys/src/cmd/upas
+.TP
+.B /rc/bin/mail
+.TP
+.B /sys/src/cmd/upas
+source for commands in
+.B /bin/upas
+.TP
+.B /sys/src/cmd/faces
+.TP
+.B /rc/bin/vwhois
+.SH "SEE ALSO"
+.IR face (6),
+.IR rewrite (6)
+.IR ipserv (8)
+.SH BUGS
+.I Nedmail
+truncates
+long headers for searching.
+.sp
+.br
+.I Biff
+and 
+the
+.B \-b
+option of
+.I fs
+perform the same function but in slightly
+different environments.
+The duality is confusing.
+The 
+.B \-b
+option exists because starting both
+.I fs
+and
+.I biff
+in a Telnet session results in a number
+of processes that don't die when the
+session is terminated; the
+.IR plumber (4)
+is held open by
+.I fs
+and
+.I biff
+still having it mounted, while
+.I fs
+is held open by
+.I biff
+which is blocked waiting for plumbing
+input.