Intro

So we installed NodeJS on our machine.

Now we want to write a simple script, run it from the terminal & use some commandline arguments.

Write a simple script

• Open your terminal
• Create a file named index.js:

touch index.js

• Add console.log('Hello') into it:

echo "console.log('Hello')" > index.js

Run it from the terminal

• Run it:

node index.js

Use commandline arguments

• Update index.js to use the commandline arguments and print them:

echo "const args = process.argv" > index.js
echo "console.log(args)" >> index.js

• Run it with an argument:

node index.js miku86

• We are seeing an array with 3 elements:

[
'/usr/bin/node',
'/home/miku86/index.js',
'miku86'
]

args[0] is the path to the executable file, args[1] is the path to the executed file, args[2] is the additional commandline argument from step 2.

So if we want to use our additional commandline argument, we can use it like this in a JavaScript file:

console.log(args[2]);

Further Reading

• Node process.argv documentation

Questions

• Do you use the native process or some libraries like yargs? Why?