For years, Ubuntu (and most Debian based Linux distributions) have relied on a program called Synaptic Package Manager to install software. However, as of Ubuntu 11.10 Oneiric Ocelot, Synaptic has been removed from Ubuntu in favor of the Ubuntu Software Center. Ubuntu Software Center does have a nicer GUI than Synaptic. However, if you prefer Synaptic, it’s quite easy to install on Ubuntu 12.04 Precise Pangolin. Synaptic can especially come in handy as you set up a new Ubuntu installation, since you can use it to search for specific packages that you might need.
To install Synaptic on Ubuntu 12.04 Precise Pangolin, go to the Terminal (to find the Terminal, click on the Dash and search for Terminal) and type this command:
sudo apt-get install synaptic
Enter your password to authenticate, and apt-get will download and install Synaptic for you.
After the installation is complete, you can launch Synaptic by searching for “Synaptic” in the Dash and click on the program’s icon. You’ll need to enter your password for authentication before Synaptic launches.