mh-alias.5mh

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH mh-alias 5mh
.SH Name
mh-alias \- alias file for MH message system
.SH Description
.NXR "mh-alias file"
.NXR "MH system" "alias file"
Aliasing allows you to send mail to a person or group of persons 
without typing their complete mail address.
Both your MH personal alias file and
the system alias file for mail delivery, 
.PN /usr/lib/mh/MailAliases ,
process aliases in the same way.
You can specify the name of your personal alias file in your 
.PN \&.mh_profile .
.PP
A line of the alias file can have the following formats:
.EX
alias : address-group
alias ; address-group
< alias-file
.EE
.PP
The first line of the example is the standard format.
The alias appears at the start of the line, 
followed by a colon, followed by the address or addresses
that it represents.
.PP
If the alias is terminated with a semicolon (;)
instead of a colon (:), the mail system outputs both 
the alias and the address-list in the correct format.
.PP
If the line starts with a \f(CW<\fR,
the file named after the \f(CW<\fR 
is read for more alias definitions.
The reading is done recursively, so a
\f(CW<\fR
can occur in the beginning of an alias file with the expected results.
.PP
Addresses can be expressed in the following formats:
.EX
alias: address1, address2, address3, ...
alias: <file
alias: =ULTRIX-group
alias: +ULTRIX-group
alias: *
.EE
.PP
Addresses are normally given in a list,
separated by a comma and one or more spaces.
If the list goes over one line,
you can create a continuation line by placing a back-slash (\e)
immediately before the new-line character.
.PP
If the address-group begins with a \f(CW<\fR,
the file named after the \f(CW<\fR is read 
and its contents added to the address list for the alias.
.PP
If the address-group starts with an 
\f(CW=\fR,
then the file 
.PN /etc/group
is consulted for the ULTRIX-group named after the 
\f(CW=\fR.
Each login name occurring as a member of the group is added to the
address list for the alias.
.PP
If the address-group starts with a 
\f(CW+\fR,
then the file 
.PN /etc/group
is consulted
to determine the group-id of the ULTRIX-group named after the 
\f(CW+\fR.
Each login name occurring in the 
.PN /etc/passwd
file whose group-id is indicated by this group 
is added to the address list for the alias.
.PP
If the address-group is simply 
\f(CW*\fR,
then the file 
.PN /etc/passwd
is consulted and all login names with a user-id 
greater than a given number (usually 200) 
are added to the address list for the alias.
.PP
Aliases are resolved at posting time in the following way.
A list of all the addresses from the message is built and duplicate
addresses are eliminated.
If the message originated on the local host,
then alias resolution is performed for those addresses in the message
that have no host specified.
For each line in the alias file,
aliases are compared against all of the existing addresses.
If there is a match, the matched alias is removed from the address list, 
and each new address in the address-group is added to the address list, 
if it is not already on the list.
.PP
The alias itself is not usually output;
the address-group that the alias maps to is output instead.
However, if the alias is terminated with a semicolon (;) 
instead of a colon (:), both the alias and the address 
are output in the correct format.
This makes replies possible, because in MH aliases and
personal aliases are unknown to the mail transport system.
.\"
.\" .PP
.\" Because the alias file is read line by line, 
.\" forward references work; 
.\" but backward references are not recognized, 
.\" so there is no recursion.
.\"
.PP
MH alias files are expanded into the headers of messages posted.
This aliasing occurs first, at posting time,
without the knowledge of the message transport system.
In contrast, once the message transport system is given a message 
to deliver to a list of addresses, 
for each address that appears to be local,
a system-wide alias file is consulted.  
These aliases are not expanded into the headers of messages delivered.
.PP
An alias file must not reference itself directly, 
or indirectly through another
alias file, using the 
\f(CW<file\fR 
construct.
.\"
.\"
.SS Using Aliasing
To use aliasing in MH, you need to set up a personal alias file.
It can have any name, but it is usually called 
.PN aliases ,
and is usually located in your Mail directory.
To set up the file, you need to perform the following steps.
.PP
First, add the following line to your
.PN \&.mh_profile :
.EX
Aliasfile: aliases
.EE
If you have chosen a different name for your file, 
you should use this instead of
.PN aliases .
If your file is in a directory other than your Mail directory,
you must supply the full pathname.
.PP
Next, create the file 
.PN aliases
in your Mail directory.
.PP
You can now start to add aliases to your 
.PN aliases
file.
.\"
.\"
.\"
.\"
.SH Examples
This section gives an example of an alias file, 
followed by an explanation of the entries:
.EX
sgroup: fred, fear, freida
fred: frated@UCI
ULTRIX-committee: <ultrix.aliases
staff: =staff
wheels: +wheel
everyone: *
.EE
.PP
On the first line of the example,
\f(CWsgroup\fR
is defined as an alias for the three names
\f(CWfrated@UCI\fR,
\f(CWfear\fR,
and
\f(CWfreida\fR.
On the second line of the example,
\f(CWfred\fR
is defined as an alias for
\f(CWfrated@UCI\fR.
Next, the definition of 
\f(CWULTRIX-committee\fR
is given by reading the file 
\f(CWultrix.aliases\fR
in your Mail directory.
The alias
\f(CWstaff\fR
is defined as all users who are listed as members of the group 
\f(CWstaff\fR
in the 
.PN /etc/group
file.
The alias
\f(CWwheels\fR
is defined as all users whose group-id in
.PN /etc/passwd
is equal to the group
\f(CWwheel\fR.
Finally, the alias
\f(CWeveryone\fR
is defined as all users with a user-id in
.PN /etc/passwd
greater than 200.
.\"
.\"
.\"
.\"
.SH Files
.TP 10
.PN /usr/lib/mh/MailAliases
System alias file.
.TP 10 
.PN $HOME/.mh_profile
Your user profile.
.\"
.\"
.\"
.\"
.SH See Also
ali(1mh), send(1mh), whom(1mh),
group(5), passwd(5), 
mh_profile(5mh), mtstailor(5mh),
conflict(8mh), post(8mh)