测试页面02

1、第一页

解释内容
create database hero;

2、第二页

解释第二页
[root@centos7 etc]# touch {4,6,7}b.txt
[root@centos7 etc]# ls -d /etc/[^[:alpha:]][[:alpha:]]*
/etc/4b.txt /etc/6b.txt /etc/7b.txt

第三页

ssh-keygen -t dsa -P  '' -f ~/.ssh/id_dsa  > /dev/null  2>&1
ssh-copy-id  -i ~/.ssh/id_dsa.pub  192.168.192.16
ssh-copy-id  -i ~/.ssh/id_dsa.pub  192.168.192.17
ssh-copy-id  -i ~/.ssh/id_dsa.pub  192.168.192.18
ssh-copy-id  -i ~/.ssh/id_dsa.pub  192.168.192.19

第四页

ssh-keygen -t dsa -P  '' -f ~/.ssh/id_dsa  > /dev/null  2>&1
ssh-copy-id  -i ~/.ssh/id_dsa.pub  192.168.192.16
ssh-copy-id  -i ~/.ssh/id_dsa.pub  192.168.192.17
ssh-copy-id  -i ~/.ssh/id_dsa.pub  192.168.192.18
ssh-copy-id  -i ~/.ssh/id_dsa.pub  192.168.192.19