Centipede
The game is called centipede but it's website is no longer being maintained. This is a bash game requiring no downloads and an interesting study for those interested in bash scripts.
Options
You can change the size of the screen to make it smaller and more challenging by changing these variables:
LASTCOL=40 # Last col of game area
LASTROW=20 # Last row of game area
Check out options for getting "pretty characters":
# Prettier characters but not supported
# by all termtypes/locales
#SNAKECHAR="\0256" # Character to use for snake
#WALLCHAR="\0244" # Character to use for wall
#APPLECHAR="\0362" # Character to use for apples
#
# Normal boring ASCII Chars
SNAKECHAR="@" # Character to use for snake
WALLCHAR="X" # Character to use for wall
APPLECHAR="o" # Character to use for apples
Remove the comment from the first three code lines and add a comment (#) to the last three code lines.
Complete bash code
Here's the complete code:
#!/bin/bash
#
# Centipede game
#
# v2.0
#
# Author: [email protected]
#
# Functions
drawborder() {
# Draw top
tput setf 6
tput cup $FIRSTROW $FIRSTCOL
x=$FIRSTCOL
while [ "$x" -le "$LASTCOL" ];
do
printf %b "$WALLCHAR"
x=$(( $x + 1 ));
done
# Draw sides
x=$FIRSTROW
while [ "$x" -le "$LASTROW" ];
do
tput cup $x $FIRSTCOL; printf %b "$WALLCHAR"
tput cup $x $LASTCOL; printf %b "$WALLCHAR"
x=$(( $x + 1 ));
done
# Draw bottom
tput cup $LASTROW $FIRSTCOL
x=$FIRSTCOL
while [ "$x" -le "$LASTCOL" ];
do
printf %b "$WALLCHAR"
x=$(( $x + 1 ));
done
tput setf 9
}
apple() {
# Pick coordinates within the game area
APPLEX=$[( $RANDOM % ( $[ $AREAMAXX - $AREAMINX ] + 1 ) ) + $AREAMINX ]
APPLEY=$[( $RANDOM % ( $[ $AREAMAXY - $AREAMINY ] + 1 ) ) + $AREAMINY ]
}
drawapple() {
# Check we haven't picked an occupied space
LASTEL=$(( ${#LASTPOSX[@]} - 1 ))
x=0
apple
while [ "$x" -le "$LASTEL" ];
do
if [ "$APPLEX" = "${LASTPOSX[$x]}" ] && [ "$APPLEY" = "${LASTPOSY[$x]}" ];
then
# Invalid coords... in use
x=0
apple
else
x=$(( $x + 1 ))
fi
done
tput setf 4
tput cup $APPLEY $APPLEX
printf %b "$APPLECHAR"
tput setf 9
}
growsnake() {
# Pad out the arrays with oldest position 3 times to make snake bigger
LASTPOSX=( ${LASTPOSX[0]} ${LASTPOSX[0]} ${LASTPOSX[0]} ${LASTPOSX[@]} )
LASTPOSY=( ${LASTPOSY[0]} ${LASTPOSY[0]} ${LASTPOSY[0]} ${LASTPOSY[@]} )
RET=1
while [ "$RET" -eq "1" ];
do
apple
RET=$?
done
drawapple
}
move() {
case "$DIRECTION" in
u) POSY=$(( $POSY - 1 ));;
d) POSY=$(( $POSY + 1 ));;
l) POSX=$(( $POSX - 1 ));;
r) POSX=$(( $POSX + 1 ));;
esac
# Collision detection
( sleep $DELAY && kill -ALRM $$ ) &
if [ "$POSX" -le "$FIRSTCOL" ] || [ "$POSX" -ge "$LASTCOL" ] ; then
tput cup $(( $LASTROW + 1 )) 0
stty echo
echo " GAME OVER! You hit a wall!"
gameover
elif [ "$POSY" -le "$FIRSTROW" ] || [ "$POSY" -ge "$LASTROW" ] ; then
tput cup $(( $LASTROW + 1 )) 0
stty echo
echo " GAME OVER! You hit a wall!"
gameover
fi
# Get Last Element of Array ref
LASTEL=$(( ${#LASTPOSX[@]} - 1 ))
#tput cup $ROWS 0
#printf "LASTEL: $LASTEL"
x=1 # set starting element to 1 as pos 0 should be undrawn further down (end of tail)
while [ "$x" -le "$LASTEL" ];
do
if [ "$POSX" = "${LASTPOSX[$x]}" ] && [ "$POSY" = "${LASTPOSY[$x]}" ];
then
tput cup $(( $LASTROW + 1 )) 0
echo " GAME OVER! YOU ATE YOURSELF!"
gameover
fi
x=$(( $x + 1 ))
done
# clear the oldest position on screen
tput cup ${LASTPOSY[0]} ${LASTPOSX[0]}
printf " "
# truncate position history by 1 (get rid of oldest)
LASTPOSX=( `echo "${LASTPOSX[@]}" | cut -d " " -f 2-` $POSX )
LASTPOSY=( `echo "${LASTPOSY[@]}" | cut -d " " -f 2-` $POSY )
tput cup 1 10
#echo "LASTPOSX array ${LASTPOSX[@]} LASTPOSY array ${LASTPOSY[@]}"
tput cup 2 10
echo "SIZE=${#LASTPOSX[@]}"
# update position history (add last to highest val)
LASTPOSX[$LASTEL]=$POSX
LASTPOSY[$LASTEL]=$POSY
# plot new position
tput setf 2
tput cup $POSY $POSX
printf %b "$SNAKECHAR"
tput setf 9
# Check if we hit an apple
if [ "$POSX" -eq "$APPLEX" ] && [ "$POSY" -eq "$APPLEY" ]; then
growsnake
updatescore 10
fi
}
updatescore() {
SCORE=$(( $SCORE + $1 ))
tput cup 2 30
printf "SCORE: $SCORE"
}
randomchar() {
[ $# -eq 0 ] && return 1
n=$(( ($RANDOM % $#) + 1 ))
eval DIRECTION=\${$n}
}
gameover() {
tput cvvis
stty echo
sleep $DELAY
trap exit ALRM
tput cup $ROWS 0
exit
}
###########################END OF FUNCS##########################
# Prettier characters but not supported
# by all termtypes/locales
#SNAKECHAR="\0256" # Character to use for snake
#WALLCHAR="\0244" # Character to use for wall
#APPLECHAR="\0362" # Character to use for apples
#
# Normal boring ASCII Chars
SNAKECHAR="@" # Character to use for snake
WALLCHAR="X" # Character to use for wall
APPLECHAR="o" # Character to use for apples
#
SNAKESIZE=3 # Initial Size of array aka snake
DELAY=0.2 # Timer delay for move function
FIRSTROW=3 # First row of game area
FIRSTCOL=1 # First col of game area
LASTCOL=40 # Last col of game area
LASTROW=20 # Last row of game area
AREAMAXX=$(( $LASTCOL - 1 )) # Furthest right play area X
AREAMINX=$(( $FIRSTCOL + 1 )) # Furthest left play area X
AREAMAXY=$(( $LASTROW - 1 )) # Lowest play area Y
AREAMINY=$(( $FIRSTROW + 1)) # Highest play area Y
ROWS=`tput lines` # Rows in terminal
ORIGINX=$(( $LASTCOL / 2 )) # Start point X - use bc as it will round
ORIGINY=$(( $LASTROW / 2 )) # Start point Y - use bc as it will round
POSX=$ORIGINX # Set POSX to start pos
POSY=$ORIGINY # Set POSY to start pos
# Pad out arrays
ZEROES=`echo |awk '{printf("%0"'"$SNAKESIZE"'"d\n",$1)}' | sed 's/0/0 /g'`
LASTPOSX=( $ZEROES ) # Pad with zeroes to start with
LASTPOSY=( $ZEROES ) # Pad with zeroes to start with
SCORE=0 # Starting score
clear
echo "
Keys:
W - UP
S - DOWN
A - LEFT
D - RIGHT
X - QUIT
If characters do not display properly, consider changing
SNAKECHAR, APPLECHAR and WALLCHAR variables in script.
Characters supported depend upon your terminal setup.
Press Return to continue
"
stty -echo
tput civis
read RTN
tput setb 0
tput bold
clear
drawborder
updatescore 0
# Draw the first apple on the screen
# (has collision detection to ensure we don't draw
# over snake)
drawapple
sleep 1
trap move ALRM
# Pick a random direction to start moving in
DIRECTIONS=( u d l r )
randomchar "${DIRECTIONS[@]}"
sleep 1
move
while :
do
read -s -n 1 key
case "$key" in
w) DIRECTION="u";;
s) DIRECTION="d";;
a) DIRECTION="l";;
d) DIRECTION="r";;
x) tput cup $COLS 0
echo "Quitting..."
tput cvvis
stty echo
tput reset
printf "Bye Bye!\n"
trap exit ALRM
sleep $DELAY
exit 0
;;
esac
done
