Hard shutdown is the opposite of graceful shutdown: insteand of allowing the OS (operating system) to properly shut down its processes and close the connections, the OS is turned off immediately. While it saves some time, it might cause unexpected problems or data loss, or even failure to boot.
What Does Require Do
When a module is loaded using the require() function, the module’s code is executed and the exports object of the module is returned. The require() function can be used to load local files as well as modules installed from npm.