finley makes it easy to quickly decompile several .NET binaries concurrently without involving a GUI.

It does this by extending the CLI implementation of ILSpy (https://github.com/icsharpcode/ILSpy). ILSply is an open source .NET decompiler. It is normally invoked as a GUI application. However, its CLI implementation ('ilspycmd') provides a better platform for automation.

• Recursive decompilation of .NET binaries in a given directory
• Duplicate .NET binary avoidance
• Configurable concurrent decompilation of .NET binaries

My primary use case for this application is to decompile all of the .NET files in a given directory into a new directory whose structure mimics that of the original directory.

I would like this to happen as quickly as possible too. That means the application must support running multiple decompilers simultaneously. Lastly, I would like to avoid decompiling the same .NET files over and over. Some developers (who shall not be named) like to include the same .NET files multiple times in their work.

All of these things are headaches that a simple script could never solve. That is why finley exists :)

Before using finley, you must install ilspycmd. This requires the .NET Core SDK. If you are a chocolatey user, you can install this by running:

choco install dotnetcore-sdk -y

After installing .NET Core SDK, you can install ilspycmd by executing the following command:

dotnet tool install -g ilspycmd --version 6.0.0.5559-preview2

Note: the version number of ilspycmd is explicitly provided. This is because, at the time of writing this post, the current non-preview version of ilspycmd does not support the shipping version of .NET Core.

Typically, finley is used to decompile a directory containing .NET binaries:

finley some-directory

If you would like to recursively decompile all of the binaries in a given directory (i.e., include sub-directories), you can add the -r option:

finley -r some-directory

For additional options, run with the -h option. This will produce a list of options and an explanation of their effects:

  -allow-duplicates
    	Decompile file even if its hash has already been encountered
  -e string
    	Comma separated list of file extensions to search for (default ".dll,.exe")
  -h	Display this help page
  -ilspy string
    	The 'ilspycmd' binary to use (default "ilspycmd")
  -no-ilspy-errors
    	Exit if ILSpy fails to decompile a file
  -num-workers int
    	Number of .NET decompiler instances to run concurrently (default n)
  -o string
    	The output directory. Creates a new directory if not specified
  -r	Scan recursively
  -respect-file-case
    	Respect filenames' case when matching their extensions
  -v	Display log messages rather than a progress bar
  -version
    	Display the version number and exit

You can use any of the following methods to build the application:

• go build cmd/finley/main.go - Build the application
• build.sh - A simple wrapper around 'go build' that saves build artifacts to build/ and sets a version number in the compiled binary. This script expects a version to be provided by setting an environment variable named VERSION
• buildwin.sh - Build the application for Windows (since that seems like the most common OS this tool would be used on)