How To Pass Command-Line Arguments to Node.js Program

Written by Rahul, Updated on August 1, 2019

Node.js stores all the command line arguments in an array. The first element of an array is the node command (binary location) itself. The second element is the javascript file we refer to that often comes after the node command. After that, the arguments are stored in third, fourth and so on.

To understand this create a sample Node.js script and execute script with some arguments. For example, assuming the following script for process-args.js:

// print process.argv
process.argv.forEach((val, index) => {
  console.log(`${index}: {val}`);
});

// print process.argv

process.argv.forEach((val, index) => {

console.log(`${index}: {val}`);

});

Launching the Node.js process as:

node process-args.js hello "Rahul Kumar" 123

Would generate the output:

0: /usr/local/bin/node
1: /home/rahul/process-args.js
2: hello
3: Rahul Kumar
4: 123

To access the single argument, simply use process.argv[INDEX] option. Change index number as per your need.

console.log(process.argv[0]);

1	console.log(process.argv[0]);

console.log(process.argv[2]);

1	console.log(process.argv[2]);

Rahul

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