Ubuntu 16.04: Install VirtualBox for virtualization

Install virtualbox package. virtualbox-ext-pack needs license agreement.

$ sudo apt install -y virtualbox virtualbox-guest-additions-iso \
virtualbox-ext-pack
<snip>
Do you accept the terms of the VirtualBox PUEL license? [yes/no] yes

You can use expect for skipping license agreement.

$ sudo apt install -y expect
$ expect -c "
set timeout -1
spawn sudo apt install -y virtualbox virtualbox-guest-additions-iso virtualbox-ext-pack
expect \"Do you accept the terms of the VirtualBox PUEL license? \\\\\\[yes/no\\\\\\] \"
send \"yes\n\"
expect eof
"

Run virtualbox command.

$ virtualbox