- in your virtual machine netstat - in an error, to install the corresponding software package
! [picture description] (https://dn-simplecloud.shiyanlou.com/courses/uid1252982-20200313-1584090919938)
- install netstat corresponding error packages
! [picture description] (https://dn-simplecloud.shiyanlou.com/courses/uid1252982-20200313-1584091068800)
- perhaps because in the domestic source of mirror, no update

Sudo rm/var/lib/apt/lists/* - vf

Sudo apt to get the update: update software source

- an error or update software source
! [picture description] (https://dn-simplecloud.shiyanlou.com/courses/uid1252982-20200313-1584092264960)
- may be forced off the terminal (such as Ctrl + Z), forced to unlock

Sudo rm/var/cache/apt/archives/lock

Sudo rm/var/lib/DPKG/lock