shell脚本实例-matrix

[Sat Feb 27 17:51:36 1038 /dev/pts/0 192.168.2.250 ~/sh]#cat matrix
blue="\033[0;34m"
brightblue="\033[1;34m"
cyan="\033[0;36m"
brightcyan="\033[1;36m"
green="\033[0;32m"
brightgreen="\033[1;32m"
red="\033[0;31m"
brightred="\033[1;31m"
white="\033[1;37m"
black="\033[0;30m"
grey="\033[0;37m"
darkgrey="\033[1;30m"

colors=($blue $brightgreen $grey)
spacing=${1:-100}
scroll=${2:-0}
screenlines=$(expr `tput lines` - 1 + $scroll)
screencols=$(expr `tput cols` / 2 - 1)
chars=(a b c d e f g h i j k l m n o p q r s t u v w x y z 1 2 3 4 5 6 7 8 9 0 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z)

count=${#chars[@]}
colorcount=${#colors[@]}

trap "tput sgr0; clear; exit" SIGTERM SIGINT

if [[ $1 =~ "-h" ]]
  then
  echo "display a matrix screen in the terminal"
  echo "usage:          matrix [SPACING [SCROLL]]"
  echo "example: matrix 100 0"
  exit 0
fi

clear
tput cup 0 0

while :
  do
  for i in $(eval echo {1..$screenlines})
    do
     for i in $(eval echo {1..$screenlines})
      do
      rand=$(($RANDOM%$spacing))
      case $rand in
       0)
        printf "${colors[$RANDOM%$colorcount]}${chars[$RANDOM%$count]} ";;
       1)
        printf "  ";;
       *)
        printf "\033[2C";;
      esac
     done
     printf "\n"
    done
    tput cup 0 0
done