CSharpDecompiler is a crossplatform console tool for decompiling .dll files to .cs, based on ILSpy.
Usage examples (on Mac):
mono CSharpDecompiler.exe MyApp.dll // decompiles MyApp.dll to console
mono CSharpDecompiler.exe assemblies -p --regex='^(?!System\.|Mono\.)' --output=src // decompiles all .dll and .exe files from assemblies directory that don't start with System. or Mono. to src in parallel (multithreaded) mode.
mono CSharpDecompiler.exe /? // show help