Windows 10 has been out for a year as a free upgrade from Windows 7, 8, and 8.1. Excepting some hacky workarounds the upgrade is no-longer available for free to users. Brett Howse has an article with the major changes that are available today in the Windows 10 anniversary update.
The biggest feature for me is the awkwardly named Bash on Ubuntu on Windows. Microsoft has a long history of picking poor names for their UNIX subsystems including the awkwardly named Services for Unix. Services for Unix was Microsoft’s hedge of interoperability to please third-party businesses, but it was always hindered by Microsoft’s desire to compete with Linux. The options to install and update applications were limited to what you could compile because SFU didn’t include any kind of package management system. The only choices left were either shelling out to a Linux machine, cygwin (which is a huge pain in the ass), dual-booting, or installing Linux in a virtual machine.
Bash on Ubuntu on Windows been available in a preview form to beta testers (Windows Insiders) for a while, it’s a more complete version of command-line utilities and an environment you would commonly get on a Linux desktop or server developed with Ubuntu‘s owner, Canonical. Though you still have to jump through some hoops to install it, it’s very promising that BoUoW includes Ubuntu’s package management system and native Linux command-line utilities that haven’t been recompiled for Windows.
I hope this extends to GUI applications some day, but the focus for Microsoft this time is on attracting developers.