stdin: Invalid argument
mount: mounting /cow on /root/cow failed: No such file or directory
passwd: password expiry information changed.
dbus-daemon[913]: [session uid=999 pid=913] Activating service name='org.gtk.vfs.Daemon' requested by ':1.0' (uid=999 pid=914 comm="" label="unconfined")
dbus-daemon[913]: [session uid=999 pid=913] Successfully activated service 'org.gtk.vfs.Daemon'
dbus-daemon[913]: [session uid=999 pid=913] Activating service name='org.gtk.vfs.Metadata' requested by ':1.0' (uid=999 pid=914 comm="" label="unconfined")
fuse: device not found, try 'modprobe fuse' first
dbus-daemon[913]: [session uid=999 pid=913] Successfully activated service 'org.gtk.vfs.Metadata'
A connection to the bus can't be made
Using CD-ROM mount point /cdrom/
Identifying... [529bc2251b7638771c96d095bcda64ee-2]
Scanning disc for index files...
Found 4 package indexes, 0 source indexes, 0 translation indexes and 1 signatures
Found label 'Xubuntu 20.04 LTS _Focal Fossa_ - Beta amd64 (20200408)'
This disc is called: 
'Xubuntu 20.04 LTS _Focal Fossa_ - Beta amd64 (20200408)'
Copying package lists...gpgv: Signature made Wed Apr  8 02:04:50 2020 UTC
gpgv:                using RSA key D94AA3F0EFE21092
gpgv: Good signature from "Ubuntu CD Image Automatic Signing Key (2012) <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 20.04 LTS _Focal Fossa_ - Beta amd64 (20200408)]/ focal main multiverse restricted universe
Repeat this process for the rest of the CDs in your set.