Linux for Developers Course
Linux for Developers
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Intermediate

curl

Definition

Client URL. A command-line tool for transferring data over various network protocols (HTTP, HTTPS, FTP). It is the industry standard for testing APIs from the terminal.

Explain Like I'm New

A web browser without a screen. You ask for a website, and instead of showing you pictures, it just dumps the raw HTML code onto your terminal.

Real World Example

A developer is writing a REST API. To test it, they type `curl -X POST -d '{"user":"bob"}' http://localhost:3000/api/users`. The terminal prints out the JSON response from the server.

Common Use Cases

  • •Testing APIs
  • •Downloading files
  • •Automated web requests

Interview Questions

basic

  • Does `curl` process JavaScript or render images like Chrome does?

intermediate

  • What does the `-i` flag do in a `curl` command?

Flash Cards

Question

Render JavaScript?

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Answer

No. `curl` only fetches the raw text payload. It has no rendering engine.

Question

What is -i?

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Answer

Include Headers. It forces `curl` to print the hidden HTTP headers (like Status Code 200 OK or 404 Not Found) before printing the actual webpage data.