Here’s how to backup cached / downloaded packages in Linux Mint / Ubuntu:
1. Issue to following command at the terminal to install aptoncd (Linux Mint already has this program installed) -
sudo apt-get install aptoncd
2. Now, issue the following command at the terminal -
3. Click ‘Create’.
4. The aptoncd program will list all the cached and downloaded (via apt) packages on your system. You can exclude any specific packages if you want. If you have downloaded and *.apt file manually, use ‘Add’ button to add that package to the list. Finally, have blank CDs/DVDs handy and click ‘Burn’. (To later on restore packages at a later date, click ‘Restore’ in step 3 and use the media previously created using aptoncd).