To use the dotnet command line to publish a project for a COBOL application on .NET Core you use the dotnet publish command as follows:
dotnet publish [project-name.cblproj]
The dotnet publish command includes more options than those shown above. For more information on the dotnet publish command see Microsoft: .NET fundamentals - dotnet publish.
Once you have published your project, see Microsoft: .NET fundamentals - .NET application publishing overview for information on which published files you need to deploy.
Example
To publish the only project in the current directory to use framework-dependent deployment (FDD), run the following command:
dotnet publish --self-contained false