NAME
tknewsbiff - pop up a window when news appears
SYNOPSIS
tknewsbiff [ server or config-file ]
INTRODUCTION
tknewsbiff pops up a window when there is unread news in your favorite
newsgroups and removes the window after you’ve read the news.
tknewsbiff can optionally play a sound, start your newsreader, etc.
SELECTING NEWSGROUPS
By default, the configuration file ~/.tknewsbiff describes how
tknewsbiff behaves. The syntax observes the usual Tcl rules - however,
even if you don’t know Tcl, all but the most esoteric configurations
will be obvious.
Each newsgroup (or set of newsgroups) to be watched is described by
using the "watch" command. For example:
watch dc.dining
watch nist.*
watch comp.unix.wizard -threshold 3
watch *.sources.* -threshold 20
For each newsgroup pattern, any newsgroup that matches it and which you
are subscribed to (according to your newsrc file) is eligible for
reporting. By default, tknewsbiff reports on the newsgroup if there is
at least one unread article. The "-threshold" flag changes the
threshold to the following number. For example, "-threshold 3" means
there must be at least three articles unread before tknewsbiff will
report the newsgroup.
If no watch commands are given (or no configuration file exists), all
groups which are subscribed to are watched.
To suppress newsgroups that would otherwise be reported, use the
"ignore" command. For example, the following matches all comp.* and
nist.* newgroups except for nist.posix or .d (discussion) groups:
watch comp.*
watch nist.*
ignore nist.posix.*
ignore *.d
The flag "-new" describes a command to be executed when the newsgroup
is first reported as having unread news. For example, the following
lines invoke the UNIX command "play" to play a sound.
watch dc.dining -new "exec play /usr/local/sounds/yumyum.au"
watch rec.auto* -new "exec play /usr/local/sounds/vroom.au"
You can cut down on the verbosity of actions by defining procedures.
For example, if you have many -new flags that all play sound files, you
could define a sound procedure. This would allow the -new
specification to be much shorter.
proc play {sound} {
exec play /usr/local/sounds/$sound.au
}
watch dc.dining -new "play yumyum"
watch rec.auto* -new "play vroom"
As an aside, you can put an "&" at the end of an "exec" command to get
commands to execute asynchronously. However, it’s probably not a good
idea to do this when playing sound files anyway.
"newsgroup" is a read-only variable which contains the name of the
newsgroup that is being reported. This is useful when the action is
triggered by a pattern. For example, the following line could run the
newsgroup name through a speech synthesizer:
watch * -new {
exec play herald.au
exec speak "New news has arrived in $newsgroup."
}
The flag "-display" describes a command to be executed every time the
newsgroup is reported as having unread news. The special command
"display" is the default command. It schedules $newsgroup to be
written to tknewsbiff’s display when it is rewritten. For example, by
explicitly providing a -display flag that omits the display command,
you can disable the display of newsgroups that are already reported via
-new.
watch dc.dining -new {exec play yumyum.au} -display {}
If you want to execute an action repeatedly and still display the
newsgroup in the default manner, explicitly invoke the display command
via the -display flag. For example:
watch *security* -display {
exec play red-alert.au
display
}
Actions associated with the -new and -display flags are executed only
once for each matching newsgroup. The command executed is the one
associated with the first pattern in the configuration file that
matches and observes the given threshold.
Any command that is simply listed in the configuration file is executed
each time before the update loop in tknewsbiff. The reserved (but
user-defined) procedure "user" is run immediately after the newsgroups
are scheduled to be written to the display and before they are actually
written.
For example, suppose unread articles appear in several rec.auto groups
and you play the same sound for each one. To prevent playing the sound
several times in a row, make the -new command simply set a flag. In
the user procedure, play the sound if the flag is set (and then reset
the flag).
The user procedure could also be used to start a newsreader. This
would avoid the possibility of starting multiple newsreaders just
because multiple newsgroups contained unread articles. (A check
should, of course, be made to make sure that a newsreader is not
already running.)
MORE VARIABLES
The following example lines show variables that can affect the behavior
of tknewsbiff
set delay 120
set server news.nist.gov
set server_timeout 60
set newsrc ~/.newsrc
set width 40
set height 20
set active_file /usr/news/lib/active
tknewsbiff alternates between checking for unread news and sleeping
(kind of like many undergraduates). The "delay" variable describes how
many seconds to sleep.
The "server" variable names an NNTP news-server. The default is
"news". The "server" variable is only used if the "active_file"
variable is not set.
The "server_timeout" variable describes how how many seconds to wait
for a response from the server before giving up. -1 means wait forever
or until the server itself times out. The default is 60 seconds.
The "newsrc" variable describes the name of your .newsrc file. By
default, tknewsbiff looks in your home directory for a newsrc file. A
server-specific newsrc is used if found. For example, if you have set
server to "cubit.nist.gov", then tknewsbiff looks for ~/.newsrc-
cubit.nist.gov. (This is the Emacs gnus convention - which is very
convenient when you read news from multiple servers.) If there is no
server-specific newsrc, tknewsbiff uses ~/.newsrc.
The "width" variable describes the width that tknewsbiff will use to
display information. If any newsgroup names are long enough, they will
be truncated so that the article counts can still be shown. You can
manually resize the window to see what was truncated. However, if your
configuration file sets the width variable, the window will be restored
to that size the next time that tknewsbiff checks for unread news and
updates its display.
The "height" variable describes the maximum height that tknewsbiff will
use to display information. If fewer newsgroups are reported,
tknewsbiff will shrink the window appropriately. You can manually
resize the window but if your configuration file sets the height
variable, the window will be restored to that size the next time that
tknewsbiff checks for unread news and updates its display.
The "active_file" variable describes the name of the news active file.
If set, the active file is read directly in preference to using NNTP
(even if the "server" variable is set). This is particularly useful
for testing out new configuration files since you can edit a fake
active file and then click button 2 to immediately see how tknewsbiff
responds (see BUTTONS below).
If the environment variable DOTDIR is set, then its value is used as a
directory in which to find all dotfiles instead of from the home
directory. In particular, this affects the tknewsbiff configuration
file and the .newsrc file (assuming the newsrc variable is not set
explicitly).
WATCHING DIFFERENT NEWS SERVERS
To watch multiple servers, run tknewsbiff multiple times. (Since you
need different .newsrc files and the servers have different newsgroups
and article numbers anyway, there is no point in trying to do this in a
single process.)
You can point tknewsbiff at a different server with an appropriate
argument. The argument is tried both as a configuration file name and
as a suffix to the string "~/.tknewsbiff-". So if you want to watch
the server "kidney", store the tknewsbiff configuration information in
~/.tknewsbiff-kidney". The following two commands will both use that
configuration file.
tknewsbiff kidney
tknewsbiff ~/.tknewsbiff-kidney
In both cases, the actual server to contact is set by the value of the
server variable in the configuration file.
If no configuration file is found, the argument is used as the server
to contact. This allows tknewsbiff to be run with no preparation
whatsoever.
If the argument is the special keyword "active" (or ends in "/active"),
it is used as the name of an active file. This is in turn used to
initialize the variable "active_file" so that tknewsbiff reads from the
active file directly rather than using NNTP.
Creating your own active file is a convenient way of testing your
configuration file. For example, after running the following command,
you can repeatedly edit your active file and trigger the update-now
command (either by pressing button 2 or setting the delay variable very
low) to see how tknewsbiff responds.
The active file must follow the format of a real active file. The
format is one newsgroup per line. After the newsgroup name is the
number of the highest article, the lowest article. Lastly is the
letter y or m. m means the newsgroup is moderated. y means posting is
allowed.
WINDOW
When unread news is found, a window is popped up. The window lists the
names of the newsgroups and the number of unread articles in each
(unless suppressed by the -display flag). When there is no longer any
unread news, the window disappears (although the process continues to
run).
BUTTONS
Button or key bindings may be assigned by bind commands. Feel free to
change them. The default bind commands are:
bind .list <1> help
bind .list <2> update-now
bind .list <3> unmapwindow
By default button 1 (left) is bound to "help". The help command causes
tknewsbiff to pop up a help window.
By default, button 2 (middle) is bound to "update-now". The update-now
command causes tknewsbiff to immediately check for unread news. If
your news server is slow or maintains a very large number of
newsgroups, or you have a large number of patterns in your
configuration file, tknewsbiff can take considerable time before
actually updating the window.
By default, button 3 (right) is bound to "unmapwindow". The
unmapwindow command causes tknewsbiff to remove the window from the
display until the next time it finds unread news. (The mapwindow
command causes tknewsbiff to restore the window.)
As an example, here is a binding to pop up an xterm and run rn when you
hold down the shift key and press button 1 in the listing window.
bind .list <Shift-1> {
exec xterm -e rn &
}
Here is a similar binding. However it tells rn to look only at the
newsgroup that is under the mouse when you pressed it. (The
"display_list" variable is described later in this man page.)
bind .list <Shift-1> {
exec xterm -e rn [lindex $display_list [.list nearest %y]] &
}
OTHER COMMANDS AND VARIABLES
Built-in commands already mentioned are: watch, ignore, display, help,
update-now, unmapwindow, and mapwindow.
Any Tcl and Tk command can also be given. In particular, the list of
newsgroups is stored in the list widget ".list", and the scroll bar is
stored in the scrollbar widget ".scroll". So for example, if you want
to change the foreground and background colors of the newsgroup list,
you can say:
.list config -bg honeydew1 -fg orchid2
These can also be controlled by the X resource database as well.
However, the configuration file allows arbitrarily complex commands to
be evaluated rather than simple assignments.
Certain Tcl/Tk commands can disrupt proper function of tknewsbiff.
These will probably be obvious to anyone who knows enough to give these
commands in the first place. As a simple example, the program assumes
the font in the list box is of fixed width. The newsgroups will likely
not align if you use a variable-width font.
The following variables are accessible and can be used for esoteric
uses. All other variables are private. Private variables and commands
begin with "_" so you don’t need to worry about accidental collisions.
The array "db" is a database which maintains information about read and
unread news. db($newsgroup,hi) is the highest article that exists.
db($newsgroup,seen) is the highest article that you have read.
A number of lists maintain interesting information. "active_list" is a
list of known newsgroups. "seen_list" is a list of newsgroups that
have been seen so far as the -new and -display flags are being
processed. "previous_seen_list" is "seen_list" from the previous
cycle. "ignore_list" is the list of newsgroup patterns to ignore.
"watch_list" is the list of newsgroup patterns to watch.
"display_list" is the list of newsgroup will be displayed at the next
opportunity.
UPDATING YOUR FILES
tknewsbiff automatically rereads your configuration file each time it
wakes up to check for unread news. To force tknewsbiff to reread the
file immediately (such as if you are testing a new configuration or
have just modified your newsrc file), press button 2 in the display
(see BUTTONS above).
CAVEATS
tknewsbiff defines the number of unread articles as the highest
existing article minus the highest article that you’ve read. So if
you’ve read the last article in the newsgroup but no others, tknewsbiff
thinks there are no unread articles. (It’s impossible to do any better
by reading the active file and it would be very time consuming to do
this more accurately via NNTP since servers provide no efficient way of
reporting their own holes in the newsgroups.) Fortunately, this
definition is considered a feature by most people. It allows you to
read articles and then mark them "unread" but not have tknewsbiff
continue telling you that they are unread.
UNWARRANTED CONCERNS
Your news administrator may wonder if many people using tknewsbiff
severely impact an NNTP server. In fact, the impact is negligible even
when the delay is very low. To gather all the information it needs,
tknewsbiff uses a single NNTP query - it just asks for the active file.
The NNTP server does no computation, formatting, etc, it just sends the
file. All the interesting processing happens locally in the tknewsbiff
program itself.
BUGS
The man page is longer than the program.
SEE ALSO
"Exploring Expect: A Tcl-Based Toolkit for Automating Interactive
Programs" by Don Libes, O’Reilly and Associates, January 1995.
AUTHOR
Don Libes, National Institute of Standards and Technology
1 January 1994