CHDB(7) CHDB(7)
NAME
chdb - chess database browser
SYNOPSIS
chdb [ file ... ]
DESCRIPTION
Chdb reads the given files of chess games (hist by default)
and accepts commands to search, play through, and display
the games in these files. If x is the name of the file, it
is looked for under the names x, x.m.out, and
/lib/chess/x.m.out.
After reading the files, chdb displays a chess board, a text
window with a command line, and vertical and horizontal
scroll bars along the edges of the board. The text window
holds 6 lines of information about the game and position
and, at the bottom, a command line in which to type. The
displayed text contains chess symbols-use a suitable font.
The vertical scroll bar scans through the games to select a
game; the horizontal bar then scans through the moves of the
selected game. Both scroll bars use button 1 to scan back-
wards, button 3 to scan forwards, and button 2 to jump to an
absolute position. With buttons 1 and 3, the scroll bars
are calibrated in units of 1 through 8 corresponding to the
ranks and files of the board. The units measure games on
the vertical scroll bar, ply (half-moves) on the horizontal
scroll bar. For example, clicking button 3 on the horizon-
tal scroll bar under the d file steps through the game two
full moves.
Moves may be made on the chess board by pointing with button
1. There are two methods to point at moves. For the first
method, point at the piece to be moved, press button 1,
point to the place to move that piece, and release button 1.
In the second method, point at the place where a piece is to
move and press button 1. The smallest/least-central piece
that can move there is highlighted. Releasing button 1
without moving the mouse will make the highlighted move.
Moving the mouse to the desired piece and releasing the but-
ton will move the selected piece.
Typed lines of text are echoed in the command line and exe-
cuted. The available commands are:
f n n
Set the format for display of moves in the text window.
The first number is the verbosity, with 0 minimal. The
second number is 0 for algebraic, 1 for English, and 2
Page 1 Plan 9 (printed 4/20/24)
CHDB(7) CHDB(7)
for figurine (default).
g n Go to the game with ordinal number n in the input
files. If n is prefixed with a + or -, it is inter-
preted as a relative position in the current set of
games (see below). N defaults to +1.
p n Go to whole move n in the current game. If n is pre-
fixed with a + or -, it is interpreted as an offset in
ply from the current position. N defaults to +1.
k n Mark the current set of games with tag n (see patterns,
below).
w type file
Write the current set of games to file. Type is either
a (write the games as text) or m (write the games in
binary format suitable for chdb).
Patterns select subsets of the games. A pattern is one of
the following, in decreasing precedence order. Parentheses
can be used for grouping.
. The current game.
* All games originally read.
'n The games previously marked with a k command with the
same n.
[]
[number]
All games in * that contain the positions that can be
reached in the specified number of plies from the cur-
rent position. A missing number is the same as zero,
meaning just the current position. Positions are
matched with black/white transpositions.
/regular expression/fields
This pattern matches the regular expression against the
various text windows. Fields is a list of characters
from the set abdefoprw. A is for all, b for black, d
for date, e for event, f for file, o for opening, p for
person (white and black), r for result, and w for
white. If multiple fields are given, the expression is
matched on the union of the specified fields. If no
field is given, p is assumed.
!pattern
The set subtraction of * and the given pattern.
Page 2 Plan 9 (printed 4/20/24)
CHDB(7) CHDB(7)
pattern-pattern
The set subtraction of the given patterns.
pattern+pattern
pattern|pattern
The set union of the given patterns.
pattern pattern
pattern&pattern
The set intersection of the given patterns.
+pattern
-pattern
&pattern
|pattern
These patterns have the current set of games as an
implied first operand.
EXAMPLE
Select games that Botvinnik lost:
(/Botv/w/0-1/r)|(/Botv/b/1-0/r)
FILES
/lib/chess directory of databases.
SOURCE
/sys/src/cmd/chdb
SEE ALSO
regexp(6).
BUGS
The browser is only a prototype.
Most of the databases are protected by copyright and not
distributed.
Page 3 Plan 9 (printed 4/20/24)