Linux之shell脚本打印圣诞树

#!/bin/bash
#########################################################################
# File Name: 123.sh
# Author: LookBack
# Email: admin#dwhd.org
# Version:
# Created Time: Tue 13 Oct 2015 12:40:48 AM CST
#########################################################################

PrintA() {
        a=$1
        b=`printf "%-${a}s\n" "*" | sed 's/\s/*/g'`
        c=`echo "(39-$a)/2"|bc`
        [ "$a" != "39" ] && d=`printf "%-${c}s\n"` || d=""
        echo "${d}${b}"
}

PrintB() {
        e=$1
        b=`printf "%-5s\n" "*" | sed 's/\s/*/g'`
        c=`echo "($e-5)/2"|bc`
        d=`printf "%-${c}s\n" " "`
        echo -e "${d}${b}\n${d}${b}\n${d}${b}\n${d}${b}\n${d}${b}\n${d}${b}"
}

for i in `seq 1 2 39`; do
        [ "$i" = "39" ] && PrintB $i || PrintA $i
done

======改进版 能根据终端大小自动调整圣诞树的大小====

#!/bin/bash
#########################################################################
# File Name: christmas.sh
# Author: LookBack
# Email: admin#dwhd.org
# Version:
# Created Time: Tue 13 Oct 2015 10:17:55 AM CST
#########################################################################

NUM1=$(awk '{a=($1-2)*0.8}{printf("%d\n",int(a)==a?a:(int(a)+1))}' <<< $(tput lines))
NUM2=`awk '{a=-1;for(i=1;i<=$1;i++){a+=2}}END{print a}' <<< $NUM1`

PrintA() {
        a=$1 && b=$2
        c=`printf "%-${a}s\n" "*" | sed 's/\s/*/g'`
        d=`echo "($b-$a)/2"|bc`
        [ "$a" != "$b" ] && e=`printf "%-${d}s\n" " "` || e=""
        echo "`printf "%-10s"`${e}${c}"
        if [ "$a" = "$b" ]; then
                c=`printf "%-5s\n" "*" | sed 's/\s/*/g'`
                d=`echo "($a-5)/2+10"|bc`
                e=`printf "%-${d}s\n"`
                echo -e "${e}${c}\n${e}${c}\n${e}${c}\n${e}${c}\n${e}${c}\n${e}${c}"
        fi
}

for i in `seq 1 2 $NUM2`; do
        PrintA $i $NUM2
done