If node.js commands won't do anything ...
This is an esoteric problem, which hit me when uglifyjs simply wouldn't do anything and just exited with an error code with any printout.
The problem might be, that you are using Ubuntu. Why? Because Ubuntu has a program called "node" which has nothing to do with node.js, that's why. And because this tool simply can't be used to run node.js-programs. Sounds logical right?
What to do? Uninstall "node" and maybe install "nodejs-legacy" if your executable complains about a missing node-bin.
If your installation is somehow screwed up beyond repair, follow the instruction in the link to cleanly reinstall the whole shebang.