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... [bda0be56db84dfd3f091adbda884ec0a-2]
Scanning disc for index files...
Found 4 package indexes, 0 source indexes, 0 translation indexes and 1 signatures
Found label 'Xubuntu 15.04 _Vivid Vervet_ - Alpha amd64 (20150115)'
This disc is called: 
'Xubuntu 15.04 _Vivid Vervet_ - Alpha amd64 (20150115)'
Copying package lists...gpgv: Signature made Thu Jan 15 10:13:10 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:[Xubuntu 15.04 _Vivid Vervet_ - Alpha amd64 (20150115)]/ vivid main multiverse restricted universe
Repeat this process for the rest of the CDs in your set.