SQL Server is Microsoft’s enterprise relational database offering. It was first released in 1989 and has seen support on various Windows and OS/2 platforms since it’s release. In October 2017, Microsoft released SQL Server 2017 for Linux. To date, Ubuntu 16, Red Hat Enterprise Linux 7.3 and 7.4 as well as SUSE Enterprise Linux Server v12 are supported.
Though the Linux distribution is missing features found in the Windows offering, the result is a very useful and feature-rich database that fits in well in a UNIX environment.
Mark calls this a minimalist guide, but he does cover a lot of the basics.