Five Practical Uses of the curl Command

The curl command is a powerful tool used to transfer data from or to a server using various protocols such as HTTP, HTTPS, FTP, and more. It’s a must-have utility for developers, system administrators, and IT professionals. Below are five practical uses of curl that can help you in your daily tasks.

1. Downloading Files from the Internet

curl is commonly used to download files from a remote server. Here’s a basic example:

curl -O https://example.com/file.zip

The -O option tells curl to save the file with its original name.

2. Sending GET Requests to APIs

You can use curl to test APIs by sending HTTP GET requests:

curl https://api.github.com/users/octocat

This is useful for retrieving data from RESTful APIs for debugging or automation purposes.

3. Sending POST Requests with Data

curl can also send POST requests with form data or JSON payloads:

curl -X POST -d "name=John&age=30" https://example.com/form

Or send JSON:

curl -X POST -H "Content-Type: application/json" -d '{"name":"John","age":30}' https://example.com/api

4. Downloading a File with a Custom User-Agent

Sometimes servers behave differently based on the user-agent. You can spoof it with:

curl -A "Mozilla/5.0" https://example.com

This can be handy for testing or scraping scenarios.

5. Checking HTTP Response Headers

To inspect response headers from a server, use the -I option:

curl -I https://example.com

This will show only the headers, helping with debugging HTTP issues or verifying server behavior.

Conclusion

The curl command is incredibly versatile. Whether you're downloading files, testing APIs, or inspecting headers, curl has a solution for you. Mastering it can save you a lot of time in the command line.