With the arrival of Visual Studio 2015 Update 1, henceforth Update 1, comes a new C# read-evaluate-print-loop (REPL), available as a new interactive window within Visual Studio 2015 or as a new command-line interface (CLI) called CSI. In addition to bringing the C# language to the command line, Update 1 also introduces a new C# scripting language, traditionally saved into a CSX file.
Before delving into the details of the new C# scripting, it’s important to understand the target scenarios. C# scripting is a tool for testing out your C# and .NET snippets without the effort of creating multiple unit testing or console projects. It provides a lightweight option for quickly coding up a LINQ aggregate method call on the command line, checking the .NET API for unzipping files, or invoking a REST API to figure out what it returns or how it works. It provides an easy means to explore and understand an API without the overhead of a yet another CSPROJ file in your %TEMP% directory.