Linux 运维工具-下载多个链接wget，aria2c

 1. wget link1 link2 ... linkN

wget link1 \
     link2 \
     link3 

 2. wget -i <links.txt>之下载多个link

create a `links.txt` include all links

http://example.com/pkg1.zip
http://example.com/pkg2.zip
http://example.com/pkg3.zip

Download all links via `wget -i`

$ wget -i links.txt

 3. aria2c 并行下载

aria2c -i links.txt