Generating locales...
  en_US.UTF-8... done
Generation complete.
pwconv: failed to change the mode of /etc/passwd- to 0600
ln: /root/usr/sbin/anacron: File exists
Using CD-ROM mount point /cdrom/
Identifying... [9582daeba41325c53e9a18aac9a51269-2]
Scanning disc for index files...
Found 2 package indexes, 0 source indexes, 0 translation indexes and 1 signatures
Found label 'Ubuntu 15.04 _Vivid Vervet_ - Alpha amd64 (20150116)'
This disc is called: 
'Ubuntu 15.04 _Vivid Vervet_ - Alpha amd64 (20150116)'
Copying package lists...gpgv: Signature made Fri Jan 16 08:36:32 2015 UTC using DSA key ID FBB75451
gpgv: Good signature from "Ubuntu CD Image Automatic Signing Key <cdimage@ubuntu.com>"

Reading Package Indexes... 0%

Reading Package Indexes... Done
Writing new source list
Source list entries for this disc are:
deb cdrom:[Ubuntu 15.04 _Vivid Vervet_ - Alpha amd64 (20150116)]/ vivid main restricted
Repeat this process for the rest of the CDs in your set.