NodeJS: How To Run Scripts From The Terminal & Use Arguments

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

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Questions

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

Comments

[André Adriano]

Cool article. Last time I had to do a project with node on the terminal I used meow. It helps with flag creation and automatically creates a --help flag.

[Shawon Ashraf]

You can also use yargs for that. I haven't tried meow yet but seems intriguing.

[miku86]

Hey André & Shawon,

thanks for your feedback.
I usually use yargs & I will check out meow.

After looking at npm trends, I will also take a look at commander.