Add Flash Player support to Firefox (Shockwave Flash addon)

To install Flash Player in Firefox download the tar.gz file from https://get.adobe.com/flashplayer/

Unpack the archive using:

tar -xzf flash_player_npapi_linux.x86_64.tar.gz

Then follow the instructions in the readme.txt file. In summary:

Create the /usr/lib/mozilla/plugins directory if it doesn’t exist:

sudo mkdir -p /usr/lib/mozilla/plugins

Copy the libflashplayer.so file to the plugins directory:

sudo cp libflashplayer.so /usr/lib/mozilla/plugins/libflashplayer.so

If this directory doesn’t work, see this article for alternatives: http://kb.mozillazine.org/Determining_plugin_directory_on_Linux

Then copy the remaining files in the /usr directory from the archive to their proper directories as per the readme.txt file:

sudo cp -r usr/* /usr

Now restart Firefox and in about:addons you should see the Shockwave Flash addon.