Beginner Q2: Installing software

Avi Greenbury avismailinglistaccount at
Thu Jan 14 18:00:34 UTC 2010

Thomas Blasejewicz wrote:
> AND there are quite a number of software packages I actually
> downloaded before, but which Synaptic apparently does not know (the
> search function does not find them, although they are already right
> here on my computer)

Where are they on your computer, what type of file are they and where
did you get them from? 
Synaptic only shows you software that is available in the repositories.
The repositories (or repos) are fairly large collections of software
provided and maintained by the same people that provide Ubuntu -
all of the software in the Ubuntu operating system is available from
the repositories, and might well have come straight from there,
depending on how you installed it.

The software available in the repositories is available in packages,
with a file extension of `deb'. You can download and install .deb files
manually and outside of Synaptic or apt-get or aptitude (which are all
approximately equivalent - different interfaces to the same process),
but the packages will not be found by these applications, since they
only look in the repos.
deb packages are sort-of analogous to a Windows installer (.exe
or .msi), except the configuration's already done, so you only need to
interfere if you want something non-default.

> So, what can I do to avoid the above mentioned error messages
> install software that Synaptic does not recognize
> (a search within Synaptic for example shows, that it does not find
> "Flash Player", which is definitely available in a version for Ubuntu.

You need to enable the restricted software. If you search for, and try
to install
you should be prompted to enable it. If it doesn't, go
Settings->Repositories and check all the text boxes.
By default, ubuntu doesn't install non-free
(as in freedom, see[0]) software, which includes flash player.

If you really want to download non-repository packages, you will either
use a utility called dpkg to install them, or build it from source.
Which software specifically are you interested in, it's difficult to
provide more guidance without more information?


Avi Greenbury ;)

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