/build --help
usage: build [-h] {compile,test,push} ...

Emscripten Image generator

optional arguments:
  -h, --help           show this help message and exit

command:
  {compile,test,push}  Main work command
    compile            Compile Docker images
    test               Test given tag(s) with Emscripten and WebAssembly
                       compatibility
    push               Runs a service what will push created images