Provided by: gurgitate-mail_1.10.0-1_all 
NAME
gurgitate-mail - an easy-to-use mail filter
SYNOPSIS
gurgitate-mail
DESCRIPTION
"gurgitate-mail" is a program which reads your mail and filters it according to the .gurgitate-rules.rb
file in your home directory. The configuration file uses Ruby syntax and is thus quite flexible.
It's generally invoked either through your .forward file:
"|/path/to/gurgitate-mail"
Or through your .procmailrc file:
:0:
| /path/to/gurgitate-mail
Alternatively, if you're the sysadmin at your site, or your sysadmin is friendly, you can use gurgitate-
mail as a local delivery agent. For postfix, put
mailbox_command=/opt/bin/gurgitate-mail
in /etc/postfix/main.cf. If you use any other MTA, and configure gurgitate-mail as a local delivery
agent, please tell me how! I want to include this in the documentation.
CONFIGURATION FILES
There are three configuration files used by gurgitate-mail: two are system-wide, and the third, is the
user rules file.
The two system-wide configuration files are /etc/gurgitate-rules and /etc/gurgitate-rules-default. These
are processed before and after the user rules, respectively.
/etc/gurgitate-rules is used to handle system-wide filtering needs: setting the default mailbox style to
Maildir rather than the default MBox, setting the spool directory, things like that.
The user configuration file is $HOME/.gurgitate-rules (or, alternatively, $HOME/.gurgitate-rules.rb.
Either work). You put your own rules here. If the user configuration file doesn't encounter a "return"
during processing, then the additional rules contained in /etc/gurgitate-rules-default are run. If that
also doesn't return, then mail messages are saved into the default mail spool location.
If the "-f" option is used on the commandline, then the file specified will be used and the default rules
will not. The "-f" option can be used more than once:
gurgitate-mail -f test-rules -f additional-rules
CONFIGURATION PARAMETERS
There are several parameters that you can set to change the way that gurgitate-mail behaves. You set a
config parameter by saying, for instance:
sendmail "/usr/sbin/sendmail"
which sets the "sendmail" parameter to "/usr/sbin/sendmail".
maildir
The directory you want to put mail folders into. This defaults to $HOME/Mail.
logfile
Where you went gurgitate-mail's log messages to go to. The standard location for this is
$HOME/.gurgitate.log
sendmail
The full path to the sendmail program, used to deliver mail. This can be any program that takes as
its parameters the list of addresses to deliver mail to, and that takes a mail message on standard
input.
homedir
The full path of your home directory. This defaults to whatever your actual home directory is.
spooldir
The path where the system's mail spools goes to. This defaults to "/var/spool/mail". On a Maildir
system, this should be set to the same as "homedir".
spoolfile
The mail spool file component of the full path of your mail spool. This is generally your username.
Maildir users should set this to "Maildir".
folderstyle
The style of folders you prefer. This can be (at the moment) either MBox or Maildir.
FILTER RULES
The filter rules are a series of Ruby statements, with the following methods and variables available:
Variables
from This contains the envelope "from" address of the email message. (Note that this isn't necessarily
the same as the contents of the "From:" header)
headers
This is an object containing the headers of the message. There are several methods that come with
this object:
body This contains the body of the email message. As of yet, there's nothing really interesting which
you can do with this, apart from assigning to it; you can rewrite the body of an email message this
way. Dealing with attachments is planned for a future release of "gurgitate-mail".
maildir
The directory which contains the folders, used by the "save" method when you specify a folder as
"=folder" (like Elm). Defaults to "$HOME/Mail".
homedir
Your home directory. Read-only.
logfile
The location of the "gurgitate-mail" logfile. If set to "nil", then no logging is done. Defaults
to "$HOME/.gurgitate.log".
sendmail
The location of the "sendmail" program. Used by the "forward" method. Defaults to
"/usr/lib/sendmail".
spoolfile
The location of the mail spool. Read-only.
Methods
matches(name(s),regex)
Returns "true" if the header "name" matches the regular expression "regex". If "name" is an array
of header names, then it returns true if at least one of the headers matches. Useful for testing
whether both "To:" and "Cc:" headers match.
from Returns the envelope "from" address of the email message. Note that this is the same as the bare
"from".
to Returns a HeaderBag (a kind of array) with the contents of the "To" and the "Cc" headers.
to_s As per Ruby convention, returns all the headers as a "String" object.
save(mailbox)
This saves the message to a mailbox. You can specify the mailbox as a word with an = sign in front
of it, in which case it puts it into "maildir". If you don't use the =name format, then you need to
specify an absolute pathname. If it can't write the message to the file you request it to, it'll
attempt to write it to "spoolfile".
forward(address)
This forwards the email message to another email address.
pipe(program)
This pipes the message through "program". "pipe" returns the exit code of the program that the
message was piped through.
filter(program)
This pipes the message through "program" and returns a new Gurgitate object containing the filtered
mail. (This is handy for external filters which modify email like, for example, SpamAssassin, which
adds a spam-score header.)
You can also say
filter(program) do
# code here
end
and it yields the newly-created Gurgitate object to the block.
headers
This returns the headers as an object of their own. This object has its own methods:
headers[*headernames]
This returns a HeaderBag (a subclass of array) containing the headers you asked for. You can
then use the =~ operator on this result to match the RHS regex with everything in the
HeaderBag.
You can change a header's value with "headers[name]=newvalue".
headers.match(name,regex)
Matches the header with the name "name" against the regex. This is the same as headers[name]
=~ /regex/.
headers.matches(names,regex)
Matches the headers with the names "names" against the regex. This is the same as
headers[*names] =~ /regex/.
headers.from
Returns the envelope from. You can change this with "headers.from=newaddress" too.
return
This tells "gurgitate-mail" to stop processing the email message. If you don't use "return", then
"gurgitate-mail" will continue processing the same mail again with the next rule. If there isn't a
"return" at the end of gurgitate-rules.rb, then "gurgitate-mail" will save the email message in the
normal mail spool.
log(message)
This writes a log message to the log file.
SIMPLE EXAMPLES
Here are some examples of "gurgitate-mail" rules, with explanations:
if from =~ /ebay.com/ then save("=ebay"); return; end
Any email from eBay (automatic end-of-auction notifications, for example, and outbid notices) gets filed
into the "ebay" folder.
if from =~ /root@/ then save("=root"); return; end
Any email from root (at any host) gets filed into a special folder. Useful for sysadmins monitoring
crontab email.
if headers.matches(["To","Cc"],"webmaster@") then
save("=webmaster")
return
end
Any email with a To: or Cc: line of "sysadmin" is saved to a "sysadmin" folder. Useful for people with
multiple role accounts redirected to their address.
if headers["Subject"] =~ /\[SPAM\]/ then
save("=spam")
return
end
This is a different syntax for matching patterns against headers. You can also match multiple headers in
the square brackets.
if headers["Subject","Keywords"] =~ /a bad word/ then
save("=swearing")
return
end
Searches for "a bad word" in the Subject and Keywords headers, and if it's there, saves the email in the
"swearing" folder.
if headers.matches(["To","Cc"],"mailing-list@example.com") then
pipe("|rcvstore +mailing-list")
return
end
Any email to a mailing list is piped through "rcvstore" to store it into an MH folder.
That
headers.matches(["To","Cc"],/regex/)
idiom happens often enough that there's a shorthand for it:
if to =~ /mailing-list@example.com/ then
pipe("|rcvstore +mailing-list")
return
end
Pipes the mail to the mailing list through "rcvstore".
ADVANCED EXAMPLES
Here are some slightly more clever examples to give you an idea of what you can do with "gurgitate-mail".
Let's suppose you have an email whitelist in a file called $HOME/.friends, so you can determine whether
some email is likely to be spam or not.
Then if someone on your whitelist sends you email, then you automatically save that into the "inbox"
folder:
friends=homedir+"/.friends"
if FileTest.exists?(friends) and FileTest.readable?(friends) then
File.new(friends).each do |friend|
if from =~ friend.chomp then
log "Mail from friend "+friend.chomp
save("=inbox")
return
end
end
end
Okay, if someone sends you email, and it's addressed specifically to you (and gurgitate-mail hasn't
caught it in another form already), then it might or might not be spam: put it into a "grey" folder:
my_addresses= [ /me@example\.com/i,
/me@example\.org/i,
/me@example\.net/i]; # I have three email addresses
my_addresses.each do |addr|
if headers.matches(["To","Cc"],addr) then
save("=possibly-not-spam")
return
end
end
And after that, if it's not from someone you know, and it's not addressed to your email address either,
then it's probably save to assume that it's spam:
save("=spam")
return
This can be improved by using a Bayesian filter, though; for example, Eric Raymond's bogofilter program
(http://bogofilter.sourceforge.net) can be automatically trained and used with the help of the
white/grey/black distinctions. Taking the example above, I'll adjust it by adding in calls to
bogofilter:
friends=homedir+"/.friends"
if FileTest.exists?(friends) and FileTest.readable?(friends) then
File.new(friends).each do |friend|
if from =~ friend.chomp then
log "Mail from friend "+friend.chomp
pipe("bogofilter -h") # <-- LINE ADDED HERE
save("=inbox")
return
end
end
end
"bogofilter -h" trains bogofilter that mail from whitelisted-people is not to be considered spam. Okay,
at the end of the .gurgitate-rules, change
save("=spam")
return
to
save("=spam")
pipe("bogofilter -s")
return
This trains "bogofilter" that anything which doesn't pass the rest of the filter should be considered
spam. Now for the interesting bit: Change the bit between these to use "bogofilter" to decide whether
email is to be considered spam or not:
my_addresses= [ /me@example\.com/i,
/me@example\.org/i,
/me@example\.net/i]; # I have three email addresses
my_addresses.each do |addr|
if headers.matches(["To","Cc"],addr) then
if pipe("bogofilter")==1
then
log("bogofilter suspects it might not be spam")
save("=possibly-not-spam")
else
log("bogofilter thinks it's probably spam")
save("=spam")
end
return
end
end
"bogofilter" has an exit code of "1" if it thinks the message is not spam, and "0" if it thinks the
message is spam.
Hopefully this should give you an idea of the kinds of things that you can use "bogofilter" for.
AUTHOR
Dave Brown <gurgitate-mail@dagbrown.com>
perl v5.10.0 2006-06-07 GURGITATE-MAIL(1)