Shell脚本——99乘法表和三角形、菱形

一、99乘法表

[root@localhost ~]# vim 99.sh
#!/bin/bash
sum=0
for ((a=1; a<=9; a++))
do
  for ((b=1; b<=$a; b++))
  do
  sum=$[$a*$b]
  echo -ne "$a*$b=$sum\t"
  done
echo ""
done
[root@localhost ~]# chmod +x 99.sh 
[root@localhost ~]# ./99.sh 
1*1=1	
2*1=2	2*2=4	
3*1=3	3*2=6	3*3=9	
4*1=4	4*2=8	4*3=12	4*4=16	
5*1=5	5*2=10	5*3=15	5*4=20	5*5=25	
6*1=6	6*2=12	6*3=18	6*4=24	6*5=30	6*6=36	
7*1=7	7*2=14	7*3=21	7*4=28	7*5=35	7*6=42	7*7=49	
8*1=8	8*2=16	8*3=24	8*4=32	8*5=40	8*6=48	8*7=56	8*8=64	
9*1=9	9*2=18	9*3=27	9*4=36	9*5=45	9*6=54	9*7=63	9*8=72	9*9=81

二、三角形

[root@localhost ~]# vim sanjiaoxing.sh
#!/bin/bash
for ((i=9; i>=1; i--))
do
  for ((a=1; a<=$i; a++))
  do
    echo -n " "
  done
  for ((b=9; b>=$i; b--))
  do
    echo -n "* "
  done
  echo ""
done
[root@localhost ~]# chmod +x sanjiaoxing.sh 
[root@localhost ~]# ./sanjiaoxing.sh 
         * 
        * * 
       * * * 
      * * * * 
     * * * * * 
    * * * * * * 
   * * * * * * * 
  * * * * * * * * 
 * * * * * * * * *

三、菱形

[root@localhost ~]# vim lingxing.sh

#!/bin/bash
for ((i=9; i>=1; i--))
do
  for ((a=1; a<=$i; a++))
  do
    echo -n " "
  done

  for ((b=9; b>=$i; b--))
  do
    echo -n "*"
  done

  for ((c=8; c>=$i; c--))
  do
    echo -n "*"
  done
  echo ""
done

for ((i=2; i<=9; i++))
do
  for ((a=1; a<=$i; a++))
  do
    echo -n " "
  done

  for ((b=9; b>=$i; b--))
  do
    echo -n "*"
  done

  for ((c=8; c>=$i; c--))
  do
    echo -n "*"
  done
  echo ""
done
[root@localhost ~]# chmod +x lingxing.sh 
[root@localhost ~]# ./lingxing.sh
[root@localhost ~]# ./lingxing.sh 
         *
        ***
       *****
      *******
     *********
    ***********
   *************
  ***************
 *****************
  ***************
   *************
    ***********
     *********
      *******
       *****
        ***
         *