The special notation
in the right-hand side
of an alias causes
to read its list of recipients
from an external file.
For that directive to be recognized as special, any address that
must select the
This is automatic with most configuration files but not with others.
If your configuration file does not automatically recognize the
directive, you will need to add a new rule
near the end of your rule set 0 (see
Section 29.6, "Rule Set 0"
). For example,
R:include:$* $@ $#local $: :include:$1
Beginning with V8.7
any delivery agent for which the
Section 30.8.7, F=:
is set can also process
(Note that eliminating the
flag for all delivery agent definitions
in your configuration file will disable this feature entirely.)
directive is used in
(5) files like
is literal. It must appear exactly
as shown, colons and all,
with no space between the colons and the "include."
As with any right-hand side of an alias, there may be
space between the alias colon and the lead colon of the
is the full pathname of a file
containing a list of recipients. It follows
with intervening space allowed.
should be a full pathname.
If it is a relative name (such as
), it is relative
queue directory. For all but V8
must not be quoted.
If it is quoted, the quotation marks are interpreted
as part of the filename.
may be quoted, and the quotation
marks are automatically stripped.
cannot be opened for reading for any reason,
prints the following warning and ignores any recipients that might
have been in the file:
path... Cannot open path
is "no such file or directory," "permission
denied," or something similar. If
exists and can be
reads it one line at a time. Empty lines are
ignored. Beginning with V8
, lines that begin with
character are also ignored:
# a comment
empty line is ignored
Each line in the
file is treated as a list
of one or more recipient addresses. Where there is more than
one, each should be separated from the others by commas.
addr2, addr3, addr4
The addresses may themselves be
aliases that appear to the left in the
may also be user addresses, program names, or filenames.
file may also contain additional
to an alias
to two recipients
to a program alias
to a file
from another file
Beginning with V8.7
Section 34.8.70, Timeout (r)
controls how long
should wait for the open to
complete. This is useful when files are remotely mounted
. This timeout encompasses both this open and
the security checks described next.
Note that the
file system must be soft mounted (or mounted with
option) for this to work.
Beginning with V8,
checks the file for security.
If the controlling user is
, all components of the path
leading to the file are also checked.
the file is set (telling
to run as owner of the file),
checks to be sure that the file is writable only
by the owner. If it is group- or world-writable,
When checking components of the path,
will print the following
warning if it is running as
and if any component
of the path is group- or world-writable:
WARNING: writable directory
This process is described in greater detail under the
debugging switch (see
Section 37.5.159, -d44.4
), which can also be used to
observe this process.
for reading but
before it reads the file, it sets the controlling user
to be the owner of the file
(if one is not already set and provided that file ownership cannot be
given away with
user provides the
identities of the sender when delivering
mail from the queue (see
Section 23.9.2, C line
file can neither deliver through programs nor append to files
if any of three situations is true:
if the owner of the
file has a shell that is not
Section 22.8.4, "The /etc/shells file"
file is world-writable,
or if the
file is group-writable and the
Section 34.8.73, UnsafeGroupWrites
) is true.
IDA and V8
files. Comment lines begin
character. If the
doesn't begin the line,
it is treated as the beginning of an address, thus allowing valid usernames
that begin with a
appear first in a line by prefixing them with a space:
Note that since comments and empty lines are ignored by
they can be used to create attractive, well-documented mailing lists.
Under older versions of
, comments can be
emulated through the use of RFC822-style comments:
( comment )
By surrounding the
in parentheses, you cause
to view it and the parentheses as an RFC-style comment
and ignore them:
( Management )
( Staff )
This form of comment works with both the old and new
As has been noted, the
should be writable only by
for security reasons.
users, such as nonprivileged department heads, cannot use the
file to create and manage mailing lists.
files allow ordinary users
(or groups of users) to maintain mailing lists. This offloads
a great deal of work from the system administrator, who
would otherwise have to manage these lists, and
gives users a sense of participation in the system.
lists is slower than
reading an entry from the
database. At busy sites
or sites with numerous mail messages addressed to mailing lists, this
difference in speed can become significant. Note that the
command-line switch (see
Section 36.7.13, -bv
can be used with
and contrast the two different forms of lists.
On the other hand, sometimes rebuilding the
can also be very slow. In such instances the
file may be faster, since it doesn't require a rebuild each time it changes.
One possible disadvantage to all types of mailing lists is that they are visible
to the outside world. This means that anyone in the world can
send mail to a local list that is intended for internal use.
Many lists are intended for
both internal and external use. One such list might be one for
discussion of the O'Reilly Nutshell Handbooks, called, say,
. Anyone inside
and anyone in the outside world
can send mail messages to this list, and those messages will
be forwarded to everyone on the