linux笔记-脚本练习

1、编写一个连接其它主机脚本，在网络畅通的情况下，只要有IP，用户和密码，就能连接。

2、编写一个创建用户的脚本，分别有存放用户名和密码的两个文件，文件中一行对应一个密码或用户，该脚本能够创建用户文件中的用户，并给用户密码文件中对应的密码，同时要考虑，文件不存在、文件行数不一致以及用户已经存在的情况。

3、数据库的备份脚本，第一个输入为密码，第二个输入为数据库名字，如果数据库名字为 --all-databases 就备份所有数据库

4、配置DDNS主服务器的脚本

#!/bin/bash
yum install bind -y
yum install dhcp -y
systemctl start named
systemctl enable named
firewall-cmd --permanent --add-service=dns
firewall-cmd --permanent --add-service=dhcp
firewall-cmd --reload

##生成密钥
cd /mnt
dnssec-keygen -a HMAC-MD5 -b 128 -n HOST hello
KEY=`cat K*.key | cut -d " " -f 7`

cp -p /etc/rndc.key /etc/hello.key
cat > /etc/hello.key < key "hello" {
        algorithm hmac-md5;
        secret "$KEY";
};
END

##配置/etc/named.conf文件
chmod 770 /var/named
sed -i 's/127\.0\.0\.1/any/g' /etc/named.conf
sed -i 's/localhost/any/g' /etc/named.conf
sed -i 's/dnssec-validation\ yes/dnssec-validation\ no/g' /etc/named.conf
cat >> /etc/named.conf << END
include "/etc/hello.key";
END

##正向解析
cat >> /etc/named.rfc1912.zones < zone "hello.com" IN {
        type master;
        file "hello.com.zone";
    allow-update { key hello; };
        allow-transfer{ 172.25.254.105;};
    also-notify {172.25.254.105;};
};
END

cp -p /var/named/named.localhost /var/named/hello.com.zone
cat > /var/named/hello.com.zone << END
\$TTL 1D
@       IN SOA  dns.hello.com. root.redhat.com. (
                                        0       ; serial
                                        1D      ; refresh
                                        1H      ; retry
                                        1W      ; expire
                                        3H )    ; minimum
        NS      dns.hello.com.
dns     A       172.25.254.67
www     A       172.25.254.100
END

##配置/etc/dhcp/dhcpd.conf文件
cat > /etc/dhcp/dhcpd.conf << END
option domain-name "hello.com";
option domain-name-servers 172.25.254.67;
ddns-update-style interim;
default-lease-time 600;
max-lease-time 7200;
log-facility local7;
subnet 172.25.254.0 netmask 255.255.255.0 {
  range 172.25.254.100 172.25.254.200;
  option routers 172.25.254.67;
}
key hello {
        algorithm hmac-md5;
        secret "$KEY";
};
zone hello.com {
        primary 127.0.0.1;
        key hello;
}
END

systemctl start dhcpd
systemctl restart named
systemctl enable dhcpd