shell脚本简单例子
eg：
Expect：
1.用环境变量RANDOM随机生成一个100以内的随机数
2.read读取当前输入
3.当前输入对比随机生成的数
4.当两个数相等时跳出苏循环，并计数（比较n次结果才相等）
1 #!/bin/bash 2 i=0 3 num=$(expr $RANDOM % 100) 4 echo $num 5 while true 6 do 7 let i++ 8 read -p "Please input number(1-100):" digit 9 if [ $digit -eq $num ]; then 10 echo $digit 11 echo "一共$i 次!!" 12 break 13 elif [ $digit -lt $num ]; then 14 echo "The number is less!" 15 elif [ $digit -gt $num -o $digit -gt 100 ]; then 16 echo "The number is bigger" 17 #elif [ $digit -gt 100 ]; then 18 # echo "not in the range!! Please reinput." 19 else 20 continue 21 fi 22 done
eg:
复习简单实例 ， 简单输入n次要取得值，最后打印出获得的所有值
1 #!/bin/bash 2 attr=() 3 num=0 4 while true 5 do 6 read -p ">>input:" name 7 attr[$num]=$name 8 echo ${attr[$num]} 9 let num++ 10 if [ $num -eq 3 ]; then 11 echo ${attr[*]} 12 exit 13 fi 14 done
eg：for循环
eg：continue和break的区别
continue结束本次循环，进行下一次循环
break跳过本次循环
1 #!/bin/bash 2 for i in `seq 10` 3 do 4 if [ $i -eq 3 ]; then 5 continue 6 else 7 echo $i 8 fi 9 done 10 11 #!/bin/bash 12 int=0 13 while : 14 do 15 let int++ 16 if [ $int -lt 10 ]; then 17 echo $int 18 else 19 break 20 fi 21 done 22 ==================== 23 for循环的用法 24 #!/bin/bash 25 for ((a=1;a<10;a++)) 26 do 27 echo $a 28 done 29 ==================== 30 嵌套循环 31 #!/bin/bash 32 for ((a=0;a<10;a++)) 33 do 34 echo "outer loop: $a" 35 for ((b=1;b<10;b++)) 36 do 37 if [ $b -eq 4 ]; then 38 continue 39 else 40 echo "inner loop: $b" 41 fi 42 done 43 done 44 ====================
shell脚本编写添加用户，随机密码后五位
1 #!/bin/bash 2 for ((i=1;i<6;i++)) 3 do 4 password=`openssl rand -hex 8 | cut -c1-5` 5 echo "$password" 6 cat /etc/passwd|grep -qa user$i 7 if [ $? -eq 0 ]; then 8 echo "user${i} already" 9 continue 10 else 11 useradd user$i;echo $a|passwd --stdin user$i 12 fi 13 done
