Next: Summary Buffer Mode Line, Previous: Summary Buffer Lines, Up: Summary Buffer Format [Contents][Index]

#### 3.1.2 To From Newsgroups

In some groups (particularly in archive groups), the `From` header isn’t very interesting, since all the articles there are written by you. To display the information in the `To` or `Newsgroups` headers instead, you need to decide three things: What information to gather; where to display it; and when to display it.

1. The reading of extra header information is controlled by the `gnus-extra-headers`. This is a list of header symbols. For instance:

       (setq gnus-extra-headers
             '(To Newsgroups X-Newsreader))

   This will result in Gnus trying to obtain these three headers, and storing it in header structures for later easy retrieval.

2. The value of these extra headers can be accessed via the `gnus-extra-header` function. Here’s a format line spec that will access the `X-Newsreader` header:

       "%~(form (gnus-extra-header 'X-Newsreader))@"

3. The `gnus-ignored-from-addresses` variable says when the ‘`%f`’ summary line spec returns the `To`, `Newsreader` or `From` header. If this regexp matches the contents of the `From` header, the value of the `To` or `Newsreader` headers are used instead.

   To distinguish regular articles from those where the `From` field has been swapped, a string is prefixed to the `To` or `Newsgroups` header in the summary line. By default the string is ‘`->` ’ for `To` and ‘`=>` ’ for `Newsgroups`, you can customize these strings with `gnus-summary-to-prefix` and `gnus-summary-newsgroup-prefix`.

A related variable is `nnmail-extra-headers`, which controls when to include extra headers when generating overview (NOV) files. If you have old overview files, you should regenerate them after changing this variable, by entering the server buffer using `^`, and then `g` on the appropriate mail server (e.g., nnml) to cause regeneration.

You also have to instruct Gnus to display the data by changing the `%n` spec to the `%f` spec in the `gnus-summary-line-format` variable.

In summary, you’d typically put something like the following in `~/.gnus.el`:

    (setq gnus-extra-headers
          '(To Newsgroups))
    (setq nnmail-extra-headers gnus-extra-headers)
    (setq gnus-summary-line-format
          "%U%R%z%I%(%[%4L: %-23,23f%]%) %s\n")
    (setq gnus-ignored-from-addresses
          "Your Name Here")

(The values listed above are the default values in Gnus. Alter them to fit your needs.)

A note for news server administrators, or for users who wish to try to convince their news server administrator to provide some additional support:

The above is mostly useful for mail groups, where you have control over the NOV files that are created. However, if you can persuade your nntp admin to add (in the usual implementation, notably INN):

    Newsgroups:full

to the end of her `overview.fmt` file, then you can use that just as you would the extra headers from the mail groups.

Next: Summary Buffer Mode Line, Previous: Summary Buffer Lines, Up: Summary Buffer Format [Contents][Index]