That node has not been updated for 6 years, so it is surprising that it still works with current node.js versions.
I have no idea what it actuall does, but the node docs say:
If one specify three parameters: unit_number, output and command, than all incoming string commands will be transformed into GlobalCache packet: [command],[unit_number]:[output],[command]
So I guess that means you have to specify msg.unit_number, msg.output and msg.command.
Thanks. That didn't work, but I can work around it. My bigger concern is your comment about how old this is. I really hope it continues to work because it's now an indispensable part of my home automation system.
I agree, for many folks it is, however, if that leads to "what OS are you running node-red on" or "what is the node-red servers locale & timeZone set to" or "what nodes do you have installed" etc, I think this could be a good first question to avoid all that to & fro.
For anyone wondering about the original question, I have found a great alternative to node-red-contrib-globalcache.
I'm currently using a tcp request node and it seems far more robust. The only catch is I need to use non-hex codes but it's no problem to get those. Let me know if anyone wants to see an example of how to do this.
It seems @Steve-Mcl is correct, assuming you are using node-red v3 then follow his advice to find the nodejs version.
If you are not using v3, and you don't know how to open a terminal on your system, you will have to tell us what OS you are using. Or perhaps google for how to open a terminal on your OS.