Understanding Process Signals

A great feature of the process module is that it allows you to register listeners to handle signals that the operating system sends to a process. This is helpful when you need to perform certain actions such as cleanup before a process is stopped or terminated. Table 9.1 lists the process events for which you can add listeners.

Table 9.1 Events that can be sent to Node.js processes

To register for a process signal, simply use the on(event, callback) method. For example, to register an event handler for the SIGBREAK event, you would use the following code:

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process.on('SIGBREAK', function(){
  console.log("Got a SIGBREAK");
});