Installing Software
There are many ways to install software—in and outside the Terminal
MANY LINUX PACKAGES are stored in what are called online “repositories.” These are channels that usually bundle together software of similar types, built for specific versions of Ubuntu (so Ubuntu 17.04’s repos aren’t the same as those for Ubuntu 16.10, or indeed 16.04). There are four main channels for each separate version: Main, Restricted, Universe, and Multiverse.
The Main repo contains free software that can be redistributed freely, and is fully supported by Ubuntu with regular updates. Universe contains a vast array of free and open source software, where the community provides updates. Restricted houses a small set of proprietary (closed source) tools and drivers required to support Ubuntu on everyday hardware, while Multiverse contains software that is not free nor supported.
These repos can then be accessed by package managers, such as Software Center, to provide you with a convenient central location for locating, installing, and— where supported—automatically updating packages. Beyond Repositories The vast majority of programs that you need can be found with these four main repos. If you find the Software Center a bit limited, try a more robust (and a little more advanced) package manager by searching for “Synaptic” to install the Synaptic Package Manager. This provides a more thorough search of repos to help you find the packages you’re looking for, and provides a more comprehensive list of programs out of the box.
Not all programs are available through the default repos—some offer their own, which you can add to your package manager one of two ways: either via “Settings > Software & Updates > Other Software,” or through the Terminal (see right). Once installed, you’re alerted to any updates when they’re made available by the software maintainers.
Other programs can be downloaded individually as packages, which work in a similar way to program installers in Windows. These contain everything that’s needed for the program to run successfully—not just programs, but references to dependencies, too, which you’re prompted to install if they’re not already on your system. These files often come with a .deb extension— save this to your Downloads folder, then double-click the file to proceed—your package manager should take over at this point. Note that while it records the installation, your package manager can’t detect any updates—that’s down to the program or its maintainer. Install From the Terminal Familiarize yourself with the “apt” range of tools, and you’ll find most of the time the Terminal is the quickest and best way to install stand-alone software packages. Start with the following command:
$ sudo apt-get update
This retrieves the latest package lists (including updated versions) from all installed repositories. The following two commands install and remove software:
$ sudo apt-get install <package> $ sudo apt-get remove <package>
The following updates all installed software:
$ sudo apt-get update && sudo apt-get upgrade
You can also add repositories via the Terminal. Many third-party repos are hosted at https://launchpad.net and can be added using the following command:
$ sudo add-apt-repository ppa:<repository name>