CSI is a simple C# interpreter and has been available for .NET 1.1, 2.0, 3.0, and 3.5 for a while now. Earlier this year, I updated CSI for .NET 4 Beta 2, and now I've (somewhat belatedly) updated it for the final, public .NET 4 Framework. Today's post is mainly about getting an official .NET 4 RTM-compiled build of CSI released, so there aren't any functional changes to the tool itself.

FYI: I have a TODO list and there are some interesting things on it - it's just that none of them seemed particularly urgent.

The links above explain what CSI is and how it works; the executive summary is that CSI offers an alternative to typical CMD-based batch files by enabling the use of the full .NET framework and stand-alone C# source code files for automating simple, repetitive tasks. It accomplishes that by compiling source code "on the fly" and executing the resulting assembly behind the scenes. The benefit is that it's easy to represent tasks with a simple, self-documenting code file that leaves no need to worry about compiling a binary, trying to keep it in sync with changes to the code, or tracking project files and remembering how to build everything.


[Click here to download CSI for .NET 4.0, 3.5, 3.0, 2.0, and 1.1 - along with the complete source code and test suite.]



  • The copy of CSI.exe in the root of the download ZIP is now the .NET 4 version because that's the latest public .NET Framework. Previous versions of CSI can be found in the Previous Versions folder: CSI11.exe, CSI20.exe, CSI30.exe, and CSI35.exe.
  • As with the previous release, I have not re-compiled the .NET 1.1 version, CSI11.exe - largely because I don't have .NET 1.1 installed anywhere. :)


Here's the "read me" file for a slightly better idea of how CSI works:

==  CSI: C# Interpreter                           ==
==  David Anson (http://blogs.msdn.com/b/delay/)  ==

CSI: C# Interpreter
     Version 2010-06-07 for .NET 4.0

Enables the use of C# as a scripting language by executing source code files
directly. The source code IS the executable, so it is easy to make changes and
there is no need to maintain a separate EXE file.

CSI (CodeFile)+ (-d DEFINE)* (-r Reference)* (-R)? (-q)? (-c)? (-a Arguments)?
   (CodeFile)+      One or more C# source code files to execute (*.cs)
   (-d DEFINE)*     Zero or more symbols to #define
   (-r Reference)*  Zero or more assembly files to reference (*.dll)
   (-R)?            Optional 'references' switch to include common references
   (-q)?            Optional 'quiet' switch to suppress unnecessary output
   (-c)?            Optional 'colorless' switch to suppress output coloring
   (-a Arguments)?  Zero or more optional arguments for the executing program

The list of common references included by the -R switch is:

CSI's return code is 2147483647 if it failed to execute the program or 0 (or
whatever value the executed program returned) if it executed successfully.

   CSI Example.cs
   CSI Example.cs -r System.Xml.dll -a ArgA ArgB -Switch
   CSI ExampleA.cs ExampleB.cs -d DEBUG -d TESTING -R

CSI was inspired by net2bat, an internal .NET 1.1 tool whose author had left
Microsoft. CSI initially added support for .NET 2.0 and has now been extended
to support .NET 3.0, 3.5, and 4.0. Separate executables are provided to
accommodate environments where the latest version of .NET is not available.

Version History

Version 2010-06-07
Update .NET 4 (RTM) version
Make .NET 4 version primary

Version 2010-01-04
Add .NET 4 (Beta 2) version
Minor updates

Version 2009-01-06
Initial public release

Version 2005-12-15
Initial internal release