#!/bin/bash
#Author:wangjun
#Contact QQ:183530300
#Version:1.0
#Create time:2016-08-17 17:27:45
#Description:random number comparative
minrandom=$RANDOM
maxrandom=$minrandom
echo $minrandom
for I in {1..9};do
RD=$RANDOM
echo $RD
if [[ $RD -gt $maxrandom ]];then
maxrandom=$RD
elif [[ $RD -lt $minrandom ]];then
minrandom=$RD
fi
done
echo "Minrandom is : $minrandom"
echo "Maxrandom is : $maxrandom"
4，打印九九乘法表（第一版）
#!/bin/bash
#Author:wangjun
#Contact QQ:18353030
#Version:1.0
#Create time:2016-08-16 13:07:40
#Description:99 multiplication table
for Row in {1..9};do
for Column in `seq $Row`;do
echo -ne "${Column}x${Row}=$[$Row*$Column]t"
done
echo
done
5，打印九九乘法表（第二版）——for循环特殊用法
#!/bin/bash
#Author:wangjun
#Contact QQ:183530300
#Version:1.0
#Create time:2016-08-18 11:35:16
#Description:multiplication table
for ((row=1;row<=9;row++));do
for ((column=1;column<=$row;column++));do
echo -ne "${column}x${row}=$[${column}*${row}]t"
done
echo
done
循环执行 ：将某代码段重复运行多次； 重复运行多少次： 循环次数事先已知 ；循环次数事先未知 ；有进入条件和退出条件。
三种循环体：for、while、until。
再循环前前介绍步进，在循环中经常用到步进。
步进
显示1-10
[root@centos6mini app]# echo {1..10}
1 2 3 4 5 6 7 8 9 10
[root@centos6mini app]# echo $(seq 1 10)
1 2 3 4 5 6 7 8 9 10
1-10 递加
[root@centos6mini app]# echo {1..10..2}
1 3 5 7 9
[root@centos6mini app]# echo $(seq 1 2 10)
1 3 5 7 9
1-10 递减
[root@centos6mini app]# echo {10..1..2}
10 8 6 4 2
[root@centos6mini app]# echo $(seq 10 -2 1)
10 8 6 4 2
1-100间的奇数和偶数
[root@centos6mini app]# echo {1..100..2}
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99
[root@centos6mini app]# echo {2..100..2}
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100
[root@centos6mini app]# echo {100..1..2}
100 98 96 94 92 90 88 86 84 82 80 78 76 74 72 70 68 66 64 62 60 58 56 54 52 50 48 46 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2
[root@centos6mini app]# echo {99..1..2}
99 97 95 93 91 89 87 85 83 81 79 77 75 73 71 69 67 65 63 61 59 57 55 53 51 49 47 45 43 41 39 37 35 33 31 29 27 25 23 21 19 17 15 13 11 9 7 5 3 1
随机生成16位包含数字、大小写字母、符号的密码
