3.3 Command list

gnuchess supports the following commands:

^C

Quit the program.

quit

Quit the program.

exit

In analysis mode this stops analysis, otherwise it quits the program.

help

Produces a help blurb corresponding to this list of commands.

usage

Produce blurb on command line options.

(Same as gnuchess --help)

book

Handle the book. Requires a subcommand:

add - compiles book.bin from book.pgn

on - enables use of book

off - disables use of book

best - play best move from book

worst - play worst move from book

random - play any move from book

prefer (default) - choose a good move from book (Method subject to variation)

version

Prints out the version of this program

(Same as gnuchess --version)

pgnsave FILENAME

Saves the game so far to the file from memory

pgnload FILENAME

Loads the game in the file into memory (cf. pgnreplay)

pgnreplay FILENAME

Loads the game in the file into memory, and enables commands first, last, next, previous. This allows replaying a saved game step by step. (cf. pgnload)

first

Go to start position of pgn loaded game with pgnreplay.

last

Go to last position of pgn loaded game with pgnreplay.

next

Advances one move in pgn loaded game with pgnreplay.

n

Advances one move in pgn loaded game with pgnreplay.

previous

Back one move in pgn loaded game with pgnreplay.

p

Back one move in pgn loaded game with pgnreplay.

force

manual

Makes the program stop moving. You may now enter moves to reach some position in the future.

(Same as gnuchess --manual)

white

Program plays black, set white to move.

Note: not implemented in this version.

black

Program plays white, set black to move.

(White and black commands are mainly for icsDrone and will cause the current en-passant capture square to be forgotten).

Note: not implemented in this version.

go

Computer takes whichever side is on move and begins its thinking immediately

easy

Disables thinking on opponent’s time

(Same as gnuchess --easy)

hard

Enables thinking on opponent’s time

post

Arranges for verbose thinking output showing variation, score, time, depth, etc.

If pondering (see hard) is on, the program will output it’s thinking whilst the opponent is thinking.

(Same as gnuchess --post)

nopost

Turns off verbose thinking output

name NAME

Lets you input your name. Also writes the log.nnn and a corresponding game.nnn file. For details please see auxillary file format sections.

result

Mostly used by Internet Chess server.

activate

This command reactivates a game that has been terminated automatically due to checkmate or no more time on the clock. However, it does not alter those conditions. You would have to undo a move or two or add time to the clock with level or time in that case.

Note: not implemented in this version.

rating COMPUTERRATING OPPONENTRATING

Inputs the estimated rating for computer and for its opponent

new

Sets up new game (i.e. positions in original positions)

time

Inputs time left in game for computer in hundredths of a second. Mostly used by Internet Chess server.

otim

Inputs time left in game for opponent in hundredths of a second. Mostly used by Internet Chess server.

random

Randomizes play by perturbing the evaluation score slightly. The degree of perturbation is adjustable.

Note: not implemented in this version. Neither in v5

hash

on - enables using the memory hash table to speed search

off - disables the memory hash table

memory N

Sets the hash table to permit storage of N MB.

null

on - enables using the null move heuristic to speed search

off - disables using the null move heuristic

xboard

on - enables use of xboard/winboard

off - disables use of xboard/winboard

(Same as gnuchess --xboard)

depth N

Sets the program to look N ply (half-moves) deep for every search it performs. If there is a checkmate or other condition that does not allow that depth, then it will not be

level MOVES MINUTES INCREMENT

Sets time control to be MOVES in MINUTES with each move giving an INCREMENT (in seconds, i.e. Fischer-style clock).

load

epdload

Loads a position in EPD format from disk into memory.

save

epdsave

Saves game position into EPD format from memory to disk.

switch

Switches side to move

Note: not implemented in this version.

solve FILENAME

solveepd FILENAME

Solves the positions in FILENAME

remove

Backs up two moves in game history

undo

Backs up one move in game history

show

Requires a subcommand:

board - displays the current board

time - displays the time settings

moves - shows all moves using one call to routine

escape - shows moves that escape from check using one call to routine

noncapture - shows non-capture moves

capture - shows capture moves

eval [or score] - shows the evaluation per piece and overall

game - shows moves in game history

pin - shows pinned pieces

Note: ’show eval’ and ’show pin’ not implemented in this version.

test

Requires a subcommand:

movelist - reads in an epd file and shows legal moves for its entries

capture - reads in an epd file and shows legal captures for its entries

movegenspeed - tests speed of move generator

capturespeed - tests speed of capture move generator

eval - reads in an epd file and shows evaluation for its entries

evalspeed tests speed of the evaluator

Note: not implemented in this version.

analyze

Switches program into analysis mode, this is primarily intended for communicating analysis to an external interface using the Xboard chess engine protocol. It enables "force", "post", and "hard", at the same time, whilst altering the output format of post to conform with the engine protocol.

graphic

Enables graphic mode. In this mode, the board is displayed using the Unicode chess symbols (Codepoints from U+2654 to U+265F). The graphic mode requires a terminal with Unicode support.

(Same as gnuchess --graphic)

nographic

Disables graphic mode. The board is displayed using the good-old classic view based on plain ASCII.