You can get command-line arguments passed to your node.js application by using process.argv. process.argv is actually an array. So if you want values, out of this array you'll either have to use a loop or you can get simply by putting array index in process.argv.

Suppose you have a node.js app. "myscript.js".

You have passed parameters as:
    $node myscript.js 4

Then in the code as in line number 2 of below code, we can get the parameter value as process.argv[2].
    function GetSqrt() {  
        var num = process.argv[2];  
        console.log(" Number is " + num + " and its square " + num * num);  
    }  
    GetSqrt();

You might be thinking, why I have given index number 2 and not 0. Actually process.argv[0] will return 'node' and process.argv[1] will return your script name as in this case myscript.js.

If you have multiple arguments to pass from the command prompt, you can create a separate method for argument parsing as like
    function GetSqrt() {  
       var args = ParseArguments();  
       args.forEach(function(num) {  
      
           console.log(" Number is " + num + " and its square " + num * num);  
       })  
    }  
    GetSqrt();  
      
    function ParseArguments() {  
       var input = [];  
       var arguments = process.argv;  
       arguments.slice(2).forEach(function(num) {  
           input.push(num);  
       });  
       return input;  
    }

Here arguments.slice(2) will remove first two arguments(node and your application name) from arguments array