wget -nd -r -l1  -A.rpm --no-parent http://mirrors.aliyun.com/centos/7.6.1810/os/x86_64/Packages/ -e robots=off

wget -nd -r -l1  -A.rpm --no-parent http://mirrors.163.com/centos/7.6.1810/os/x86_64/Packages/ -e robots=off

wget -nd -r -nc -p -A.rpm --no-parent http://mirrors.aliyun.com/epel/7/x86_64/Packages/ -e robots=offcd

-nd 不创建目录, wget默认会创建一个目录
-r 递归下载
-l1 (L one) 递归一层,只下载指定文件夹中的内容, 不下载下一级目录中的.
–no-parent 不下载父目录中的文件

-p 下载网页所需的所有文件，如图片等 
 

-nc:下载时跳过已经存在的文件

-e robots=off 忽略robots

下载阿里yum源 打开内容如下

 

[base]
 name=CentOS-$releasever - Base - mirrors.aliyun.com
 failovermethod=priority
 baseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/
​​​         http://mirrors.aliyuncs.com/centos/$releasever/os/$basearch/​​​         http://mirrors.cloud.aliyuncs.com/centos/$releasever/os/$basearch/
 gpgcheck=1
 gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#released updates
 [updates]
 name=CentOS-$releasever - Updates - mirrors.aliyun.com
 failovermethod=priority
 baseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/
​​​         http://mirrors.aliyuncs.com/centos/$releasever/updates/$basearch/​​​         http://mirrors.cloud.aliyuncs.com/centos/$releasever/updates/$basearch/
 gpgcheck=1
 gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#additional packages that may be useful
 [extras]
 name=CentOS-$releasever - Extras - mirrors.aliyun.com
 failovermethod=priority
 baseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/
​​​         http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/​​​         http://mirrors.cloud.aliyuncs.com/centos/$releasever/extras/$basearch/
 gpgcheck=1
 gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#additional packages that extend functionality of existing packages
 [centosplus]
 name=CentOS-$releasever - Plus - mirrors.aliyun.com
 failovermethod=priority
 baseurl=http://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/
​​​         http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/​​​         http://mirrors.cloud.aliyuncs.com/centos/$releasever/centosplus/$basearch/
 gpgcheck=1
 enabled=0
 gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#contrib - packages by Centos Users
 [contrib]
 name=CentOS-$releasever - Contrib - mirrors.aliyun.com
 failovermethod=priority
 baseurl=http://mirrors.aliyun.com/centos/$releasever/contrib/$basearch/
​​​         http://mirrors.aliyuncs.com/centos/$releasever/contrib/$basearch/​​​         http://mirrors.cloud.aliyuncs.com/centos/$releasever/contrib/$basearch/
 gpgcheck=1
 enabled=0
 gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7