Not possible with the command line as there would be too many parameters. Leverage can be automated using the COM object model and processed with any programming language that is able to automate COM including C# and .NET.

What is your use case for the Leverage? Updating the new project with translations for the old project after a software update or migrating 2 localization branches into one project?

I have two use cases for this:

1 - we have a development team that works on a branch of the LPU so that they don't mess up the real translation work and they add information into custom field etc. So for that one we just want to leverage this information into the real project file

2 - we have times that we need to send new strings to SDL for initial translation at at the same time I have bundles out to Language Specialists. So I create a temp LPU to send bundles to SDL and when they come back I leverage the translations into the real project and synchronize to send that to the Language Specialists.