linux--shell之脚本示例

shell函数练习

检查主机存活状态

- 有一个主机列表

- 将错误ip放到数组里面判断是否ping失败三次

/bin/bash
# test host living status
#host list
IP_LIST="192.168.0.1 192.168.0.2 192.168.13.141 192.168.1.7 192.168.1.8 192.168.1.6 192.168.1.5"
for IP in $IP_LIST;do
    NUM=1
    while [ $NUM -le 3 ];do
        if ping -c 1 $IP >/dev/null;then
            echo "$IP ping is successful."
            break
        else
            echo "$IP ping is faiure $NUM"
            FALL_COUNT[$NUM]=$IP
            let NUM++
        fi
    done
    #the  fail ip  to arr and ping three time
    if [ ${#FALL_COUNT[*]} -eq 3 ];then
        echo "${FALL_COUNT[1]} Ping is failure!"
        unset FALL_COUNT[*]
    fi
done


- 将错误次数放到FALL_COUNT便利那个里面判断是否ping三次失败

#!/bin/bash
# test host living status
#host list
IP_LIST="192.168.0.1 192.168.0.2 192.168.13.141 192.168.1.7 192.168.1.8 192.168.1.6 192.168.1.5"
for IP  in $IP_LIST;do
    FALL_COUNT=0
    for ((i=1;i<=3;i++));do
        if ping -c 1 $IP > /dev/null;then
            echo "$IP ping is successfull."
            break
        else
            echo "$IP ping is failure $i"
            let FALL_COUNT++
        fi
    done
    if [ $FALL_COUNT -eq 3 ];then
        echo "$IP Ping is failure~~"
    fi
done



- 利用for循环将ping通的地址跳出循环继续，如果跳不出打印ping失败

#!/bin/bash
# test host living status
#host list
IP_LIST="192.168.0.1 192.168.0.2 192.168.13.141 192.168.1.7 192.168.1.8 192.168.1.6 192.168.1.5"
ping_success_status() {
    if ping -c 1 $IP > /dev/null;then
        echo "$IP Ping is susccessful"
        continue
    fi
}

for IP in $IP_LIST;do
    ping_success_status
    ping_success_status
    ping_success_status
    echo "$IP ping is failure~~~~"
done

判断输入的是否是IP

- 第一种

#!/bin/bash
#check input is ip address?
function check_ip {
    IP=$1
    VALID_CHECK=$(echo $IP|awk -F. '$1<=255&&$2<=255&&$3<=255&&$4<=255{print "Yes"}')
    if echo $IP | grep -E "^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$" >/dev/null;then
        if [ $VALID_CHECK == "Yes" ];then
            echo "$IP is IPv4 address!!"
        else
            echo "$IP not Ipv4 address!!!"
        fi
    else
        echo "$IP Format Error~~~~"
    fi
}
check_ip 192.168.1.1
check_ip 2662.2432.232.322
check_ip ccsacascascca
check_ip a.a.a.a
check_ip 0.2.3.3
check_ip 0..32.
check_ip 10.10.3.6




- 第二种
/bin/bash
#check input is ip address?
function check_ip {
    IP=$1
    VALID_CHECK=$(echo $IP|awk -F. '$1<=255&&$2<=255&&$3<=255&&$4<=255{print "Yes"}')
    if echo $IP | grep -E "^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$" >/dev/null;then
        if [ $VALID_CHECK == "Yes" ];then
            echo "$IP is IPv4 address!!"
            return 0
        else
            echo "$IP not Ipv4 address!!!"
            return 1
        fi
    else
        echo "$IP Format Error~~~~"
        return 1
    fi
}
while true;do
    read -p "plses input one ip address:" IP
    check_ip $IP
    [ $? -eq 0 ] && break || continue
done

RHCE脚本考题

- 基础题
    - 在某台设备上创建一个名为/root/foo.sh的脚本
    - 当运行/root/foo.sh redhat是输出fedora
    - 当运行/root/foo.sh fedora是输出redhat
    - 当没有任何参数或者参数不是以上俩个则输出/root/foo.sh redhat|fedora


!/bin/bash
case $1 in
    fedora)
        echo "redhat"
        ;;
    redhat)
        echo "fedora"
        ;;
    *)
        echo "/root/foo.sh redhat|fedora"
esac



- 进阶题目
    - 创建一个添加用户的脚本
    - https://wenku.baidu.com/view/b1c071b2690203d8ce2f0066f5335a8102d26632.html


    #!/bin/bahs
    if [ $# -ne 1];then
    echo "wenjia meiyou "
    exit 1
    elif [ if $1 ];then
    for i in `cat $1`
    do
    useradd -s /bin/false $i
    done
    else
    echo "input file not found" >&2
    exit 1
    fi