How to write smart contracts in C# on ubuntu

To develop smart contracts in C# on ubuntu, basically you need to do the following:

Create a library project, write code, and add the smart contract library.
Execute neo-compiler/neon to generate the compiler.
Run neon to generate the .avm file.

Create a smart contract project

In the dotnet command line, create a library project:

mkdir NeoContractDemo 
cd ./NeoContractDemo/ 
dotnet new classlib 
rm ./Class1.cs 
vim NeoContractDemo.cs

In NeoContractDemo.cs, enter the following code and then press ESC + wq! .

using Neo.SmartContract.Framework; 
using Neo.SmartContract.Framework.Services.Neo;

public class NeoContractDemo: SmartContract 
{ 
   public static bool Main() 
   { 
       return true; 
   } 
}

Add the smart contract reference:

dotnet add package Neo.SmartContract.Framework --version 2.5.4

Compile the smart contract project：
```
dotnet publish -o ../testlib 
```

Generate the compiler

cd ..
git clone https://github.com/neo-project/neo-compiler.git
cd  ./neo-compiler/neon
dotnet publish -o ../../testlib

Generate the .avm file

cd ../../testlib
dotnet neon.dll NeoContractDemo.dll
mkdir ../output
cp NeoContractDemo.avm ../output/NeoContractDemo.avm

For complete scripts, refer to https://raw.githubusercontent.com/hunjixin/NeoContractBuildScriptOnUbuntu/master/SmartContract.sh