• Intro
• Downloads
• Community
• Development
• News
• TALK

Back up your applications

Latest revision as of 02:51, 22 November 2011

[edit] Scenario

Let us suppose that you are using a very special application. It may be possible that after a long time of use, the repository from where you downloaded your application is not available any more. It may also be possible that, after a long use, something happened to your device, and you need to reinstall your favorite application.

We are going to explain you a way to keep a copy of the DEB package of your favorite application, so that you can install it again even if the package is not available any more from the repositories.

WARNING: Downloading deb files for all the installed packages may cause the root file-system to be exhausted thereby "bricking" the device. Proceed with caution.

[edit] Needed Tools and Skills

To follow this tutorial, you need root access on your device and the following tools:

• Terminal emulator (X Terminal or SSH)
• VIM editor (Available in Extras)

[edit] Create the Archive folder

• Open a terminal emulator and create the required folders using the following command:

$ mkdir /home/user/MyDocs/apt-archive-cache
$ mkdir /home/user/MyDocs/apt-archive-cache/archives
$ mkdir /home/user/MyDocs/apt-archive-cache/archives/partial

or the equivalent

$ mkdir -p /home/user/MyDocs/apt-archive-cache/archives/partial

If you wish to use a different folder, substitute /home/user/MyDocs with the desired path.

[edit] Create Package-List

• As a normal user type the following command to create a file (package.list) that contains a list of all the packages installed on the device:

$ dpkg --get-selections|grep install|grep -v deinstall>/home/user/package.list

In case you just want to download a selection of packages from that list, you should edit it and remove the lines you do not need.

For example, if you just want to download a copy of the package abiword, then you should:

• As a normal user type the following command:

$ cat /home/user/package.list|grep abiword>/home/user/package-abiword.list

If you want to download all packages, except one of them: debconf, for example. Then you should:

• As a normal user type the following command:

$ cat /home/user/package.list|grep -v debconf>/home/user/package-without-debconf.list

[edit] Edit Package-List

After previous steps, you have a list with all the desired packages you want to download to your device. In our previous examples this list could be any one of these:

• package.list
• package-abiword.list
• package-without-debconf.list

Now you just need to edit this list in order to use it with apt-get:

• As a normal user type the following command:

$ vim /home/user/package.list 

• After vi editor is running, then type the following command:

 :%s!install!! 

• This last command will clean the lines, removing the word install and leaving just the name of the packages. Now we want to add an order for apt-get to download the desired packages, so type the following command:

 :%s!^!apt-get --force-yes -yy -d install --reinstall -o dir::cache=/home/user/MyDocs/apt-archive-cache ! 

• This last command will add to the beginning of each line the needed instructions for apt-get to only download the packages: -d install --reinstall. In order to prevent the script from stopping at any question we have inserted the --force-yes -yy option. Now we just need to save the file typing the following command:

 ZZ 

[edit] Download Packages

Executing the package-list script will download the packages.

• To execute the script we need first to get ROOT access.
• Then as ROOT type the following command:

 # sh</home/user/package.list 

You should now see the downloads in progress.

Reading package lists... Done
Building dependency tree       
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
Need to get 213kB of archives.
After this operation, 0B of additional disk space will be used.
Get:1 http://repository.maemo.org fremantle/free 100boxes 0.5.0-4 [213kB]
Fetched 213kB in 0s (538kB/s)
Download complete and in download only mode

Depending on the size of the list, this could take a long time. After it is completed, the downloaded packages can be listed with the following command:

$ ls /home/user/MyDocs/apt-archive-cache/archives|grep deb 

Nokia-N900-42-11:/home/user# ls /home/user/MyDocs/apt-archive-cache/archives|grep deb
100boxes_0.5.0-4_armel.deb
accdisplay_1.0_armel.deb
adblock-plus-1.0_1maemo0-8_all.deb
ati85_1.4.1-1_armel.deb
battlegweled_0.9-4_armel.deb
bluetooth-dun_1.0-2_armel.deb

[edit] Install Package-List

With previous steps you have downloaded all your favourite applications, for backup purposes. Now just imagine that you need to install them again from scratch, then you will need to proceed as follows:

To install all the packages from the list:

• open the package.list file in VIM
• remove the -d option from each of the lines (:%s!-d!!)
• save and execute the file again as root (# sh</home/user/package.list)

If you wish to install an individual package, execute the apt-get command separately for that package by using the specific line from the packages.list file.

Nokia-N900-42-11:/home/user# apt-get --force-yes -yy  install --reinstall -o dir::cache=/home/user/MyDocs/apt-archive-cache 100boxes   
Reading package lists... Done
Building dependency tree       
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
Need to get 0B/213kB of archives.
After this operation, 0B of additional disk space will be used.
(Reading database ... 36360 files and directories currently installed.)
Preparing to replace 100boxes 0.5.0-4 (using .../100boxes_0.5.0-4_armel.deb) ...
Unpacking replacement 100boxes ...
Setting up 100boxes (0.5.0-4) ...

[edit] Dependencies

• executing package.list will only download the package, not the dependencies. This may create problems during restore when the package dependencies are not available in the archive. Of course, this would only be a problem if the package list was a selection of the entire system package list. When downloading the entire system package list, all packages would be available and dependecies would not be an issue.
• safe way would be to remove the application via 'apt-get remove' and 'apt-get autoremove' and then use the apt-get with the -d and -o option to download the package with the dependencies.

[edit] Further Questions

If you have further questions, do not hesitate to place the question here in this section, and it will be answered in short.

You may also ask for help sending me an e-mail