[Osiris]

Source: Installing Flash in Ubuntu 9.04 with Firefox

If you’ve spent enough time over the years with Linux you know that the browser plug-in has been a source of agony for many. When plugins first became a necessity for browsing Linux was at an “early” age and adding these plugins was truly a nightmare.
That was then, this is now. During my first trials with Ubuntu 9.04 I discovered just how far the installation of browser plugins has come. This article will illustrate to you this fact.
Ideally, of course, the distribution would ship with all of the necessary plugins installed. By default there are a number of plugins already for you:
Demo Print
DivX
Quicktime
VLC (handles many media formats)
Windows Media Player
But the number one plugin is still missing. Why? The reason for flash missing is because there are actually three different flash plugins you can install. One is the official Adobe plugin and the other two are open source versions. Although I am a big supporter of open source software, both open source flash plugins are still in their infancy and are not yet up to par with the official version. I made the mistake of installing one of the open source versions and had to uninstall so I could get the official version.
How to install
As is typical for Linux, there are a number of ways to install the flash plugin. You can download the plugin from the Adobe site. You could open up a terminal window and issue the command:
sudo apt-get install flashplugin-installer
You could open up Synaptic (Add/Remove Software utility) and search for adobe and select “flashplugin-installer”.
Or you could browse to a web site that requires Flash.
The latter is the easiest and reliable.

Figure 1
When you go to a site that requires flash you will see a bar appear with a button on the right side labeled “Install Missing Plugins” (see Figure 1). Click that button and a new window will open (see Figure 2). This new window asks you to choose which flash player you want to install. There are three choices:

Figure 2
Swfdec: The GNOME version of the flash player
Adobe Flash Player: Official version
Gnash: GNU SWF player
Choose the Adobe version and click Next. You will then be warned that the Adobe Flash Player will download and install another application. This is okay. You will be required to enter your user password to continue.
Once the installation has finished you will need to click the Finish button.
Check the installation
After the installation is complete you can check it by opening up the plugins page. Do this by typing aboutlugins in the address bar. In this page you will see all installed plugins listed. The first one listed should be the most recently installed, which will be flash.
Using this method does not require you to restart Firefox. You have completed the process of installing the Adobe Flash plugin for Firefox.
Final thoughts
If you have any history with Linux then you know how much of a relief it is to be able to install browser plugins so easily. If you have any interest in using the open source version of these plugins, give them a try. You can uninstall them by looking at the aboutlugins page to know which version you have installed. When you know which plugin you have installed search for it in Synaptic and remove it. Once removed you can go through the process of installing through Firefox again.

[Brinson]

That seems to overcomplicate the process.

sudo apt-get install flashplugin-nonfree