You can use the Ubuntu Live Cd to install packages (i.e. to an older offline Ubuntu computer).
If you have a new Live CD and the Live CD in the Source.list file, comment all the repositories excepting the CD and
sudo apt-get update sudo apt-get dist-upgrade
After upgrade, uncomment all the other repositories in the source.list file.
Some computers can ask to use apt-cdrom. If so, follow the instructions that appears bellow.
apt-cdrom can add a new CDROM to APTs sources.list file (list of available repositories). It is necessary to use apt-cdrom to add CDs to the APT system, it cannot be done by hand.
Put the Live CD in the unit and use one of these commands, in this order :
test: sudo apt-cdrom --no-act add
if everything is OK: sudo apt-cdrom add
sudo apt-cdrom ident
sudo apt-cdrom -d "your-cdrom-mount-point" -r
Description and options
add is used to add a new disc to the source list. It will unmount the CDROM device, prompt for a disk to be inserted and then procceed to scan it and copy the index files. If the disc does not have a proper .disk/ directory you will be prompted for a descriptive title. APT uses a CDROM ID to track which disc is currently in the drive and maintains a database of these IDs in /var/lib/apt/cdroms.list
ident is a debugging tool to report the identity of the current disc as well as the stored file name.
-d or --cdrom : MountPoint (specify the location to mount the cdrom). This mount point must be listed in /etc/fstab and properly configured.
-r or --rename : rename a disc; change the label of a disk or override the disks given label. This option will cause apt-cdrom to prompt for a new label.
-n, --just-print, --recon or --no-act: no Changes; Do not change the sources.list file and do not write index files. Everything is still checked however.
After dist-upgrade you can test that everything is OK
sudo apt-get -f install sudo dpkg --configure -a