https://www.geeksforgeeks.org/how-to-compile-decompile-and-run-c-code-in-linux/

Use mcs compiler to create a windows executable csharphelloworld.exe from csharphelloworld.cs

mcs -out:csharphelloworld.exe csharphelloworld.cs
mono csharphelloworld.exe

To decompile this executable file run the following command:

monodis --output=csharphelloworld.decomp.cs csharphelloworld.exe