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How to Use curl with ipinfo.io for IP Address Lookup

ipinfo.io is a popular and robust IP address API provider that allows you to look up detailed information about any IP address, including geolocation, organization, hostname, and more. curl is a command-line tool for transferring data with URLs, supporting various protocols. Combining these two tools provides a quick and efficient way to retrieve IP information directly from your terminal.

This article will guide you through the process of using curl with ipinfo.io for IP address lookups, from basic usage to more advanced queries.

What is ipinfo.io?

ipinfo.io offers a comprehensive IP data API that can be used to gather details about an IP address. It provides a simple RESTful interface, making it easy to integrate with command-line tools like curl or programming languages. While there’s a paid tier for higher usage and more advanced features, basic lookups are free and don’t require an API key.

What is curl?

curl (Client for URLs) is a command-line utility for making requests to web servers. It’s incredibly versatile and supports a wide range of protocols including HTTP, HTTPS, FTP, and more. For our purposes, curl will be used to send HTTP GET requests to the ipinfo.io API and display the returned data.

Basic IP Address Lookup

The simplest way to use ipinfo.io with curl is to query your own public IP address. When you don’t specify an IP address, ipinfo.io automatically detects the IP address from which the request originates.

To get your public IP address and its associated information:

bash
curl ipinfo.io

Example Output:

json
{
"ip": "1.2.3.4",
"hostname": "pool-1-2-3-4.washdc.fios.verizon.net",
"city": "Ashburn",
"region": "Virginia",
"country": "US",
"loc": "39.0437,-77.4875",
"org": "AS701 Aol Transit Data Network",
"postal": "20147",
"timezone": "America/New_York",
"readme": "https://ipinfo.io/missingauth"
}

This will return a JSON object containing various details about your IP address.

Looking Up a Specific IP Address

If you want to look up information for a specific IP address (not your own), simply append the IP address to the ipinfo.io URL:

bash
curl ipinfo.io/8.8.8.8

Here, 8.8.8.8 is Google’s public DNS server.

Example Output:

json
{
"ip": "8.8.8.8",
"hostname": "dns.google",
"city": "Mountain View",
"region": "California",
"country": "US",
"loc": "37.3860,-122.0838",
"org": "AS15169 Google LLC",
"postal": "94035",
"timezone": "America/Los_Angeles",
"readme": "https://ipinfo.io/missingauth"
}

Retrieving Specific Fields

Sometimes you only need a particular piece of information, like just the country or the city. ipinfo.io allows you to request specific fields by appending the field name after the IP address (or ipinfo.io for your own IP).

To get only the city for your IP:

bash
curl ipinfo.io/city

To get only the country for 8.8.8.8:

bash
curl ipinfo.io/8.8.8.8/country

Example Output (for ipinfo.io/8.8.8.8/country):

US

You can request any of the fields returned in the full JSON output, such as ip, hostname, city, region, country, loc, org, postal, or timezone.

Using ipinfo.io with an API Token (Optional)

For higher request limits or to access certain premium features (if subscribed), you might need an API token. If you have an ipinfo.io API token, you can include it in your curl requests.

You can append it directly to the URL:

bash
curl "ipinfo.io?token=YOUR_API_TOKEN"

Or for a specific IP:

bash
curl "ipinfo.io/8.8.8.8?token=YOUR_API_TOKEN"

Replace YOUR_API_TOKEN with your actual token.

Parsing JSON Output with jq

While curl can retrieve the full JSON output, reading specific values from it manually can be cumbersome. The jq command-line JSON processor is an excellent tool to parse and filter JSON output.

First, ensure you have jq installed on your system. If not, you can usually install it via your package manager (e.g., sudo apt-get install jq on Debian/Ubuntu, brew install jq on macOS).

To extract the org (organization) field from your IP lookup:

bash
curl ipinfo.io | jq -r '.org'

To extract the city and region fields for 8.8.8.8:

bash
curl ipinfo.io/8.8.8.8 | jq -r '.city, .region'

Example Output (for curl ipinfo.io/8.8.8.8 | jq -r '.city, .region'):

Mountain View
California

The -r flag with jq ensures raw output, removing the surrounding quotes from the string values.

Conclusion

curl combined with ipinfo.io provides a powerful and convenient way to perform IP address lookups and retrieve detailed information directly from your command line. Whether you need a quick check of your own IP or detailed data for a specific address, these tools offer a flexible and efficient solution.
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