Have you ever wondered how we get software, like the apps in the App Store, or packages on the Internet to install on our devices? Wonder no more. Developers and organizations that make the software we use, generally package them up nicely for us. In most cases, all we need to do is click install and the package gets installed for us. Packaging comes in all sorts of shapes and sizes. It's just like how you'd package a gift for someone. You could put it in a box or a bag, but the contents are what really matter. Developers have different ways to package software using software compiling tools. But at the end result is a package. In the next few videos we'll discuss some of the most common package types you'll see when you work in IT support. In Windows, software is usually packaged as a dot exe or executable file. Executable files contain instructions for a computer to execute when they're run, like copy this file from here to here, install this program, or more generically, perform this operation. The concept of an executable file isn't unique to Windows, but Windows has its own special implementation of them in the form of the exe's. They're created according to Microsoft's portable executable or PE format. Although we won't get into the details of the PE format, it's good to know that exe files don't just contain instructions for the computer to perform. They also include things like text or computer code, images that the program might use, and potentially something called an msi file. A Microsoft install package or msi is used to guide a program called the Windows Installer in the installation, maintenance, and removal of programs on the Windows operating system. Besides using the GUI setup wizard to guide the user in installing the program, the Windows installer also uses the msi file to create instructions on how to remove the program, if the user wants to uninstall it. Windows executable files are usually used as starting points to bootstrap the Windows installer. In this case, they might just contain an msi file and some instructions to start the Windows installer and read it. Alternatively, executables can be used as stand-alone, custom installers, with no msi file or usage of the Windows installer. If they're packaged this way, the exe file will need to contain all the instructions that operating system needs to install the program. So, when would you use an msi file and the Windows installer? And when would you use an executable with a custom installer packaged in something like setup.exe? Great questions. If you want precise granular control over the actions Windows takes when installing your software, you might go the custom installer route. This can be tricky though, especially when managing things like code dependencies, which we'll talk about later. On the flip side, using the Windows installer guided by an msi file takes care of a lot of the bookkeeping and set up for you, but it has some pretty strict rules about how the software gets installed. As of Windows 8, Microsoft has introduced a platform to distribute programs called the Windows Store. The Windows Store is an application repository or warehouse, where you can download and install universal Windows platform apps. Those are the applications that can run on any compatible Windows devices like desktop PCs, or tablets. These programs use a format called appx to package their contents and act like a unit of distribution. We won't go into detail about appx packages, but it's good to know they're out there giving you another option for packaging software. Feel free to read more about appx packages and how to make them in the supplemental readings I've included after this video. We learned how to install exe packages in an earlier course. To install an exe from the GUI, all we need to do is double click on the executable then go through the installation process provided, either by the executable itself or the Windows installer. That's pretty straightforward, but what about installing software from the command line? And why would you need to do this in the first place? Hold onto your desktops because you're about to find out. Installing executables from the command line can be handy in lots of IT support scenarios, including automatic installations. You might want to write a script or use a configuration management tool to install some software automatically without needing a human to click buttons in an installation wizard. So, how can you install an executable from the command line? The answer, it depends. Pretty unsatisfying, I know. Running exe files from the command line is pretty simple. You open up a Command Prompt or PowerShell, change in to directory where the executable is, and type in its name. You could also just type the absolute path of the exe from wherever you are in the file system, like this, C:\users\cindy\desktop\hello.exe. Running from an installer from the command line is similar, but will potentially have more options for installation. Depending on the installer, you might have flags for things like a silent installation, where nothing shows up on the screen and the package is installed quietly, or you might get an argument to have the computer reboot automatically after the package is installed. You can check out the options for packages created by using the Microsoft Self-Extractor in the supplemental reading for a better idea of what we are talking about. A given installer might have these kinds of options for installing from the command line, but they vary from vendor to vendor. The options available for a Microsoft package might differ from the options for a Mozilla package. Pro tip, try using the slash question mark parameter when running a package from the command line to see what kinds of sub commands the package might support. If the package doesn't have any help related options, your best bet is to check out the vendor's documentation for what kinds of installations their software packages support.
