Last Updated on December 11, 2023 by Abhishek Sharma
The curl command in Linux is a versatile and powerful tool used to transfer data to or from a server using various protocols, including HTTP, HTTPS, FTP, SCP, and more. It stands for "Client URL" and is commonly utilized by developers, system administrators, and users to interact with web-based applications, APIs, download files, or perform data transfers from the command line interface.
With its ability to support a wide range of protocols and a plethora of options, curl facilitates tasks such as making HTTP requests, uploading or downloading files, testing APIs, and automating data transfers. Its flexibility and ease of use make it an invaluable tool for performing a multitude of tasks efficiently in the Linux environment.
In this article, we’ll explore the capabilities of the curl command, providing practical examples and use cases that demonstrate its functionalities across various protocols, showcasing its utility in retrieving, sending, and manipulating data over networks from the terminal.
What is curl Command in Linux with Examples?
The curl command in Linux is a versatile and powerful tool used to transfer data to or from a server using various protocols like HTTP, HTTPS, FTP, SCP, and more. It’s designed to work as a command-line tool for making requests to web servers, downloading or uploading files, testing APIs, and interacting with various network services.
Examples of curl Command in Linux:
Here are some examples showcasing the functionality of the curl command:
1. HTTP GET Request:
curl https://www.example.comThis command makes an HTTP GET request to https://www.example.com and displays the HTML content of the webpage on the terminal.
2. Download File from URL:
curl -O https://www.example.com/file.zipThe -O flag downloads the file specified by the URL and saves it with its original name in the current directory.
3. HTTP POST Request with Data:
`curl -X POST -d "param1=value1¶m2=value2” https://www.example.com/api
This command sends a POST request to https://www.example.com/api with form data specified by -d, where param1 and param2 are key-value pairs.
4. Limit Download Speed:
curl --limit-rate 1M -O https://www.example.com/largefile.isoThe –limit-rate option limits the download speed to 1 megabyte per second while downloading largefile.iso.
5. FTP File Transfer:
curl -u username:password -O ftp://ftp.example.com/file.txtThis command uses FTP to download file.txt from ftp.example.com, providing the username and password using the -u flag.
6. Follow Redirects:
curl -L https://www.example.comThe -L flag tells curl to follow redirects. If the URL redirects to another location, curl will make the request to the redirected URL.
7. Send Headers:
curl -H "Content-Type: application/json" https://www.example.com/apiUse the -H flag to send custom headers. Here, the Content-Type header is set to application/json.
These examples demonstrate how curl can be used to interact with various protocols, send requests, download files, and manipulate data from the command line in a Linux environment. The command provides a wide array of options and functionalities, making it an essential tool for various network-related tasks and automation.
Conclusion:
The curl command stands as a reliable and indispensable tool in the Linux ecosystem, offering a straightforward way to interact with various protocols and perform data transfers seamlessly from the command line. Its versatility, extensive support for different protocols, and numerous options make it an essential utility for developers, administrators, and users seeking efficient ways to retrieve or transfer data over networks.
Understanding the nuances and capabilities of curl empowers users to streamline tasks, automate processes, and efficiently handle data transfers, thus enhancing productivity within the Linux environment.
FAQs (Frequently Asked Questions) Related to curl Command in Linux with Examples:
Q1: How do I use curl to make a simple HTTP GET request?
To perform a basic HTTP GET request using curl, use the following command:
curl https://www.example.comReplace https://www.example.com with the desired URL.
Q2: Can curl be used to download files from a URL?
Yes, curl can download files from a URL. For instance:
curl -O https://www.example.com/file.zipThis command downloads the file from the specified URL and saves it with its original name in the current directory.
Q3: How can I send data with a POST request using curl?
To send data in a POST request, use the -d flag followed by the data and specify the request method with -X POST, for example:
curl -X POST -d "param1=value1¶m2=value2” https://www.example.com/apiQ4: Is it possible to limit the download speed using curl?
Yes, curl allows you to limit download speed with the –limit-rate option. For example:
curl --limit-rate 1M -O https://www.example.com/largefile.isoThis command limits the download speed to 1 megabyte per second while downloading the file.
Q5: How can I perform an FTP file transfer using curl?
To transfer files using FTP with curl, use a command similar to the following:
curl -u username:password -O ftp://ftp.example.com/file.txtReplace username, password, and the FTP URL with the appropriate credentials and file location.