1. Install aptoncd software from http://aptoncd.sourceforge.net/
Use terminal to install this software by running this command.
$ sudo apt-get install aptoncd
This software is used to make .iso file of updates/resperonities/softwares/dependencies of ubuntu which you have downloaded from internet OR installed using terminal OR installed using synaptic package manager OR installed using Ubuntu software center via INTERNET.
2.Now,whenever you install updates/resperonities/softwares/dependencies of ubuntu ....Before you shut down your computer JUST run APTonCD from System->Administration->APTonCD...than
2.(A).click on 'Create' than you will see the list of packages which you have downloaded from internet. You can add .deb packages by click on ‘Add’..
2.(B).Now click on 'Burn' ..Then select ur medium and select destination folder where .iso file will be saved....than unmark metapackage option and do not change other option and click on 'Apply'.
2.(C)Now,.iso file will be saved and APTonCD will ask for burning this .iso file to CD/DVD
But....say ‘NO/CANCLE'....because why waste CD/DVD for it??...I have solution ...
3. Install 'Furius ISO mount' software from Ubuntu software center.
Furius ISO mount:
This software is used to mount .iso and other disk image files like PowerISO and Deamon tools in Windows OS.
4. Now, Run Furius ISO mount from Applications-> Accessories.
5. Mount atponcd-********.iso file where you saved it using Furius ISO mount.
Here *******=YYYYMMDD(Date when you create .iso file).
6. Now,Copy all .deb files to specific folder from Package folder of Mounted .iso file.
7. Unmount that .iso file.
8. Whenever your ubuntu crashed, after reinstalling ubuntu,,,Paste that folder which contain all .deb files to Desktop.
Now....Run Terminal and type
$ cd Desktop
~/Desktop$ cd [folder name]
now...type 'sudo dpkg -i *.deb' without quoets....
Here * is wild card which runs files having .deb extension...
Complete....Your all .deb files will be installed.........UR softwares will be back....
This is tested by me on Ubuntu 10.10,,,
Benefit:You can take all .debs on Pen drive and give to your friend....