5.2) Installing software :
A default desktop installation will already be set up to let you update, install, and uninstall software from the internet.
Getting software from the Debian repositories or CD's and DVD's if you have no internet or a poor connection, can be done with the command line tools, dpkg, apt, and aptitude. You can also install a GUI (Graphical user interface) application manager like synaptic.
Synaptic The graphical package installer remover and updaterhttp://www.nongnu.org/synaptic/http://en.wikipedia.org/wiki/Synaptic_Package_Manager
Adding repositories and CD's or DVD's to your system:
In order for your system to know where to get new applications, libraries, plugins, and security updates, it needs to know where to get them from. This is done by adding details of the repositories and CD's to your sources.list file. This is a text file that resides in
By editing this file you can completely change the software available to your system. On a normal desktop PC you can expect to have over 20,000 “packages,” depending on the exact version you installed, and if you chose to include the “contrib” and “non-free” sections of the repositories.
Debian is a Free system and as you saw from the “social contract” only includes, and depends upon free software in the core system. All software in the “main” section of the repositories in your sources.list is Free-software.
For the convenience of it users Debian also links to “contrib” and “non-free” repositories. The “contrib” section is free software that links to or depends on some non-free software. The “non-free” section is non-free software as in proprietary, rather than cost.
This is what my current squeeze/testing sources.list looks like with comments. You will notice a hash "#" sign in front of some lines. This "comments out" or disables it and is common practice when wanting to retain information but disable it's action, or to add comments to any configuration file.
#deb cdrom:[Debian GNU/Linux testing _Squeeze_ - Official Snapshot powerpc xfce+lxde-CD Binary-1 20091123-11:38]/ squeeze main
#A short explanation: the deb part refers to the native Debian pre-compiled binary file, a deb. It's similar to a Microsoft .exe file or Mac OSX .dmg. Cdrom can point to any cdrom(s) from the package list that you may have downloaded. Then we have the mirror URL address. I'm in the UK so that's my closest. Next we have "squeeze" the version of Debian I'm running, followed by main the official free repository. If you need or choose to add contrib or non-free these would be added after main. e.g. deb http://ftp.uk.debian.org/debian/
squeeze main contrib non-free
#comment: deb-src indicates that this is linking to a source file repository. You can download the source code for any program on the system, modify it, and even build and package your own software with other tools in the repository.
#comment: Security updates are automatic by default.
#comment: This is a third party repository. It contains possibly patent encumbered code that is not included in Debian by default. Even though if may be free-software. (Were talking patents here not copyright.) You will also note that like many third party repositories, it does not respect the main, contrib, non-free protocol (even though I've not included them above, I could have). With all third party repositories it is up to you to check their status as to free-software vs. non-free, (There is an application in the repositories called "vrms" that can aid you in this.) It's up to you to check the license, security, and quality etc., of third party packages. The "Backports" repository falls under third party repository also.
Backports now officialhttp://lists.debian.org/debian-publicity/2010/09/msg00007.htmlhttp://backports-master.debian.org/Instructions/
Take care to only add Debian specific repositories. Never ones for Ubuntu or other Debian based distributions. Installing a .deb package from such sources or downloaded from the internet does not mean it will run on any Debian system. The deb may have been compiled with different setting not compatible with a real Debian system.back to the table of content