- This is what you are supposed to use this thing for—reading news.
News is generally fetched from a nearby NNTP server, and is
generally publicly available to everybody. If you post news, the entire
world is likely to read just what you have written, and they'll all
snigger mischievously. Behind your back.
- Everything that's delivered to you personally is mail. Some news/mail
readers (like Gnus) blur the distinction between mail and news, but
there is a difference. Mail is private. News is public. Mailing is
not posting, and replying is not following up.
- Send a mail to the person who has written what you are reading.
- follow up
- Post an article to the current newsgroup responding to the article you
- back end
- Gnus considers mail and news to be mostly the same, really. The only
difference is how to access the actual articles. News articles are
commonly fetched via the protocol NNTP, whereas mail
messages could be read from a file on the local disk. The internal
architecture of Gnus thus comprises a “front end” and a number of
“back ends”. Internally, when you enter a group (by hitting
<RET>, say), you thereby invoke a function in the front end in
Gnus. The front end then “talks” to a back end and says things like
“Give me the list of articles in the foo group” or “Show me article
So a back end mainly defines either a protocol (the
end accesses news via NNTP, the
nnimap back end
accesses mail via IMAP) or a file format and directory
nnspool back end accesses news via the common
“spool directory” format, the
nnml back end access mail via a
file format and directory layout that's quite similar).
Gnus does not handle the underlying media, so to speak—this is all
done by the back ends. A back end is a collection of functions to
access the articles.
However, sometimes the term “back end” is also used where “server”
would have been more appropriate. And then there is the term “select
method” which can mean either. The Gnus terminology can be quite
- Gnus will always use one method (and back end) as the native, or
default, way of getting news. Groups from the native select method
have names like ‘gnu.emacs.gnus’.
- You can also have any number of foreign groups active at the same
time. These are groups that use non-native non-secondary back ends
for getting news. Foreign groups have names like
- Secondary back ends are somewhere half-way between being native and
being foreign, but they mostly act like they are native, but they, too
have names like ‘nntp+news.gmane.org:gmane.emacs.gnus.devel’.
- A message that has been posted as news.
- mail message
- A message that has been mailed.
- A mail message or news article
- The top part of a message, where administrative information (etc.) is
- The rest of an article. Everything not in the head is in the
- A line from the head of an article.
- A collection of such lines, or a collection of heads. Or even a
collection of NOV lines.
- NOV stands for News OverView, which is a type of news server
header which provide datas containing the condensed header information
of articles. They are produced by the server itself; in the
back end Gnus uses the ones that the NNTP server makes, but
Gnus makes them by itself for some backends (in particular,
When Gnus enters a group, it asks the back end for the headers of all
unread articles in the group. Most servers support the News OverView
format, which is more compact and much faster to read and parse than the
normal head format.
The NOV data consist of one or more text lines (see Motion by Text Lines)
where each line has the header information of one article. The header
information is a tab-separated series of the header's contents including
an article number, a subject, an author, a date, a message-id,
Those data enable Gnus to generate summary lines quickly. However, if
the server does not support NOV or you disable it purposely or
for some reason, Gnus will try to generate the header information by
parsing each article's headers one by one. It will take time.
Therefore, it is not usually a good idea to set nn*-nov-is-evil
(see Slow/Expensive Connection) to a non-
nil value unless you
know that the server makes wrong NOV data.
- Each group is subscribed at some level or other (1–9). The ones
that have a lower level are “more” subscribed than the groups with a
higher level. In fact, groups on levels 1–5 are considered
subscribed; 6–7 are unsubscribed; 8 are zombies; and 9
are killed. Commands for listing groups and scanning for new
articles will all use the numeric prefix as working level.
- killed groups
- No information on killed groups is stored or updated, which makes killed
groups much easier to handle than subscribed groups.
- zombie groups
- Just like killed groups, only slightly less dead.
- active file
- The news server has to keep track of what articles it carries, and what
groups exist. All this information in stored in the active file, which
is rather large, as you might surmise.
- bogus groups
- A group that exists in the .newsrc file, but isn't known to the
server (i.e., it isn't in the active file), is a bogus group.
This means that the group probably doesn't exist (any more).
- The act of asking the server for info on a group and computing the
number of unread articles is called activating the group.
Un-activated groups are listed with ‘*’ in the group buffer.
- News servers store their articles locally in one fashion or other.
One old-fashioned storage method is to have just one file per
article. That's called a “traditional spool”.
- A machine one can connect to and get news (or mail) from.
- select method
- A structure that specifies the back end, the server and the virtual
- virtual server
- A named select method. Since a select method defines all there is to
know about connecting to a (physical) server, taking the thing as a
whole is a virtual server.
- Taking a buffer and running it through a filter of some sort. The
result will (more often than not) be cleaner and more pleasing than the
- ephemeral groups
- Most groups store data on what articles you have read. Ephemeral
groups are groups that will have no data stored—when you exit the
group, it'll disappear into the aether.
- solid groups
- This is the opposite of ephemeral groups. All groups listed in the
group buffer are solid groups.
- sparse articles
- These are article placeholders shown in the summary buffer when
gnus-build-sparse-threads has been switched on.
- To put responses to articles directly after the articles they respond
to—in a hierarchical fashion.
- The first article in a thread is the root. It is the ancestor of all
articles in the thread.
- An article that has responses.
- An article that responds to a different article—its parent.
- A collection of messages in one file. The most common digest format is
specified by RFC 1153.
- The action of sorting your emails according to certain rules. Sometimes
incorrectly called mail filtering.