#!/bin/sh## play tic-tac-toe# parse args#if [ $# -gt 1 ]; then    echo "usage: ttt [move_digit]" 1>&2    echo "       ttt quitgame" 1>&2    echo "       ttt clobber" 1>&2    exit 1elif [ $# -eq 1 ]; then    move="$1"else    move=fi# catch the clobber case#if [ clobber = "$move" ]; then    echo "ttt: rm -f ttt_game ttt_game.o ttt_game.c ttt_old.c ttt_new.c" 1>&2    rm -f ttt_game ttt_game.o ttt_game.c ttt_old.c ttt_new.c    echo "ttt: rm -f merlyn.c merlyn.o merlyn" 1>&2    rm -f merlyn.c merlyn.o merlyn    echo "ttt: removed all but the original source" 1>&2    exit 0fi# catch the quitgame case#if [ quitgame = "$move" ]; then    echo "ttt: rm -f ttt_game ttt_game.o ttt_game.c ttt_old.c ttt_new.c" 1>&2    rm -f ttt_game ttt_game.o ttt_game.c ttt_old.c ttt_new.c    echo "ttt: current game removed, perhaps you were going to lose? :-)" 1>&2    exit 0fi# watch for bad args#if [ $# -eq 1 ]; then    case "$move" in    1|2|3|4|5|6|7|8|9) ;;    *)  echo "ttt: bad argument" 1>&2	echo "usage: ttt [move_digit]" 1>&2	echo "       ttt quitgame" 1>&2	echo "       ttt clobber" 1>&2	exit 2 ;;    esacfi# be sure that we have the merlyn.c source#if [ ! -f merlyn.c ]; then    if [ -f westley.c ]; then	echo "ttt: No merlyn.c around these parts, using a copy of westley.c" 1>&2	cp westley.c merlyn.c	chmod +w merlyn.c    else	echo "ttt: Ouch!  merlyn.c and no westley.c are gone!" 1>&2	exit 3    fi    # check to see if the copy worked    if [ ! -f merlyn.c ]; then	echo "ttt: Darn, coundn't copy westley.c to merlyn.c" 1>&2	exit 4    fifi# be sure we have the merlyn program#if [ ! -f merlyn ]; then    echo "ttt: make merlyn" 1>&2    make merlyn    status=$?    if [ "$status" -ne 0 ]; then	echo "ttt: something is wrong, fix merlyn.c and build it yourself!" 1>&2	echo "     or maybe type:  ttt clobber" 1>&2	exit 5    fi    rm -f ttt_game.cfi# If we don't have a ttt_game.c, or we cannot write it, make a new ttt_game.c#if [ ! -w ttt_game.c ]; then    rm -f ttt_game.c     if [ -z "$move" ]; then	merlyn | tee ttt_game.c    else	merlyn "$move" | tee ttt_game.c    fi    chmod +w ttt_game.c# If we have a ttt_game.c, then assume that we are in the process of playing#else    rm -f ttt_game ttt_new.c    echo "ttt: make ttt_game" 1>&2    make ttt_game    status=$?    if [ "$status" -ne 0 ]; then	echo "ttt: something is wrong, fix ttt_game.c and build it yourself!" 1>&2	echo "     or maybe type:  ttt quitgame" 1>&2	exit 6    fi    if [ -z "$move" ]; then	ttt_game | tee ttt_new.c    else	ttt_game "$move" | tee ttt_new.c    fi    chmod +w ttt_new.c    if [ -s ttt_new.c ]; then	mv ttt_game.c ttt_old.c	mv ttt_new.c ttt_game.c# Check for win, lose, or draw# For a win or draw, copy merlyn.c to ttt_game.c# For a loss, copy ttt_game.c to merlyn.c, as it is now better# Also remove the executable for the file replaced# For anything else, game in progress, do not do anything	if [ -n "`grep ':-(' ttt_game.c`" ]; then	    echo	    echo "ttt: I lose...I won't make THAT mistake again!"	    chmod +w merlyn.c	    mv ttt_game.c merlyn.c	    rm -f merlyn ttt_game	else	    if [ -n "`grep ':-)' ttt_game.c`" ]; then		echo		echo "ttt: I win!"		cp merlyn.c ttt_game.c		rm -f ttt_game	    else		if [ -z "`grep 'X=-. ' ttt_game.c`" -a -z "`grep '^. ' ttt_game.c`" ]; then		    echo		    echo "ttt: It's a draw - play again?"		    cp merlyn.c ttt_game.c		    rm -f ttt_game		fi	    fi	fi    else	echo "ttt: something is wrong, maybe ttt_old.c will help" 1>&2	echo "     or maybe type:  ttt quitgame" 1>&2	echo "     or maybe type:  ttt clobber" 1>&2	exit 7    fifi