Summary - Process

Combine argv, env and child_process to write a CLI tool.

Summary - Process

In this group you learned the core tools of process management: CLI arguments with process.argv, environment variables with process.env, exit codes with process.exit, streams with process.stdin/stdout and child processes with child_process.exec.

You can combine these five tools to build a real CLI tool. For example, you can read a name from an argument, take a setting from an environment variable, set the exit code and write to stdout. This is the basic pattern of command-line tools in Node.js. Now you will combine all pieces in one piece of code.

Exercise Combine the CLI tool

Read the name from process.argv[2]; if missing, use "Node". Set process.exitCode to 0. Write the name with process.stdout.write (no newline).

Show example solution

const name = process.argv[2] || "Node";
process.exitCode = 0;
process.stdout.write(name);

Test yourself

Match each tool to its role

argv

CLI arguments
env

Environment variables
exit

Exit code
exec

Child process
What happens if process.argv[2] is not given?
```
process.argv[2]
```
- It throws an error
- The program crashes
- An empty string is returned
- undefined is returned
Show answer

undefined is returned — A missing argument is undefined; || gives a default.

Complete the default value

const name = process.argv[2] || ____;

Show answer

const name = process.argv[2] || "Node";

Next lesson: Model design

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies