Node.js process.kill() Method

The process.kill( pid[,signal] ) is an inbuilt method of node.js which sends a signal to the process, pid (which is the process id) and signal is in the string format that is the signal to send.

Syntax :

process.kill(pid[, signal])

Parameters: This method accepts two parameters as mentioned above and described below:

pid: This parameter holds the process ID.
signal: This parameter holds the string format.
signal names : These are in string format .
1. SIGTERM
2. SIGINT
3. SIGHUP

Note : If no signal specified, then by default ‘SIGTERM’ will be the signal.

‘SIGTERM’ and ‘SIGINT‘ signals have default handlers on non-Windows platforms that reset the terminal mode before exiting with code 128 + signal number. If one of these signals has a listener installed, its default behavior on node.js will be removed.
‘SIGHUP’ is generated when the console window is closed.

Return value : The process.kill() method will throw an error if the target pid is not found or doesn’t exist. This method returns boolean value 0 if pid exists and can be used as a test for the existence of the target process. For window users, this method will also throw an error if pid is used to kill a group of process.

Below examples illustrate the use of process.kill() property in Node.js:

Example 1:

index.js

// Node.js program to demonstrate the  
// process.kill(pid[, signal]) method  

// Printing process signal acknowledged 
const displayInfo = () => { 

  console.log('Receiving SIGINT signal in nodeJS.'); 
} 

// Initiating a process 

process.on('SIGINT', displayInfo); 

setTimeout(() => { 

  console.log('Exiting.'); 

  process.exit(0); 
}, 100); 

// kill the process with pid and signal = 'SIGINT'      

process.kill(process.pid, 'SIGINT');

Command to run :

node index.js

Output :

Example 2 :

index.js

// Node.js program to demonstrate the  
// process.kill(pid[, signal]) method  
// Printing process signal acknowledged 
const displayInfo = () => { 

  console.log('Acknowledged SIGHUP signal in nodeJS.'); 
} 

// Initiating a process 

process.on('SIGHUP', displayInfo); 

setTimeout(() => { 

  console.log('Exiting.'); 

  process.exit(0); 
}, 100); 

// kill the process with pid and signal = 'SIGHUP'      

process.kill(process.pid, 'SIGHUP');