It is part of the eventEmitter API in node.js. Article
It is very like popen in C languages, or subprocess in python
https://www.gnu.org/software/libc/manual/html_node/Pipe-to-a-Subprocess.html
https://docs.python.org/2/library/subprocess.html
But also different: https://dev.to/pi0/nodejs-fork-is-not-what-you-think-of-37ko https://stackoverflow.com/questions/17861362/node-js-child-process-difference-between-spawn-fork
A 2019 talk on the libuv library: https://www.youtube.com/watch?v=VfYmKD-SvjU
libuv platform abstraction library, gives node access to things like child_process — file i_o runs in the lib_uv thread pool, as well as DNS look-ups
- libuv uses two abstractions to keep track of long-running processes, handles and requests
process._getactivehandlesprocess._getactiverequests