There are a few software applications bundled with the operating system, but sooner or later you'll want to download and install some other software. Say, for example, that you want a spreadsheet application. . You can search the software repository for spreadsheet applications by typing "apt-cache search spreadsheet" at the command line prompt and pressing Enter:
pi@raspberrypi ~ $ apt-cache search spreadsheet_
This will display a huge list of available software packages, which may be a bit intimidating! Perhaps a better approach is to use an internet search engine to try and find a specific software app. The Raspbian "Wheezy" operating system gives you access to the Debian software repository, so I searched for "Debian spreadsheet application" on Google and came up with an spreadsheet application called "Gnumeric". Now you search the repository for "Gnumeric" by typing "apt-cache search gnumeric" at the command line prompt and pressing Enter:
pi@raspberrypi ~ $ apt-cache search gnumeric_
This will give you a less intimidating list of results. Now you can download and install the Gnumeric spreadsheet application by typing "sudo apt-get install gnumeric" at the command line prompt and pressing Enter:
pi@raspberrypi ~ $ sudo apt-get install gnumeric_
Your Raspberry Pi will now download and install the Gnumeric spreadsheet application, reporting its progress on your display screen as it goes. This may take a few minutes to complete, but when finished you will be returned to the Linux command line prompt.
If you have been entering the above commands directly at the command line prompt then you should start the LXDE GUI by typing "startx" and pressing Enter:
pi@raspberrypi ~ $ startx_
However, if you have been entering the above commands in a LXTerminal window, all you have to do is close the LXTerminal window.
Click on the strange looking icon at the bottom left corner of the screen to access the "Start Menu". There should now be a menu item called "Office" - place the cursor over "Office" and you should get a sub-menu containing "Gnumeric". Click on "Gnumeric" to launch the application:
If would also like a word processor application, then try searching for and installing "AbiWord":
There is a huge range of free software available for download from the Debian software repository - the only limiting factor is your imagination, and the speed of your broadband connection, however you may find that some of the apps don't run on the Raspberry Pi due to its limited processing power and RAM.