shell for循環練習題-等邊三角形

[root@localhost ~]# cat sanjiaoxing.sh 
#!/bin/bash
# Crushlinux
# 2017-04-10 
read -p "請輸入等邊三角形一條邊的長度：" long
for ((a=1;a<=long;a++))
do 
	echo -n "              "
	for (( b=$long;b>a;b--)) #控制空格輸出
	do 	
		echo  -n " "
	done
	for c in `seq 1 $a` #輸出所在行數相同的數字個數
	do 
		echo -n "$a"
	done
	for d in `seq 2 $a`   #輸出所在行數減一的數字個數
	do 
		echo -n "$a"
	done	
	echo ""  
done


[root@localhost ~]# bash sanjiaoxing.sh
請輸入等邊三角形一條邊的長度：8
                     1
                    222
                   33333
                  4444444
                 555555555
                66666666666
               7777777777777
              888888888888888