While using command line help
Import JSON, binary, or a project's skeletons into another project:
-i,
---
input Path to a folder, project, or data file to be imported.
-o,
---
output Path to project file to import into. Created if nonexistent.
-s,
---
scale Scale the project being imported.
-r,
---
import Perform a skeleton import. The skeleton name may be omitted.
I have not found any way to import into .spine project.
After using the following command I have a just regular spine editor running:
$ Spine -i warlock.json -o imported.spine -r warlock
Also scale parameter is not working
ERROR: Unrecognized command line parameter: -s