If you work with Linux, you may have come across the curl command. It’s a powerful tool used to automate downloading and uploading data from a server. Curious about how it works and what you can do with it? Keep reading.
What is the curl command?
Curl is an open-source command-line utility used to transfer data to and from servers. It supports various protocols, including HTTP, HTTPS, SFTP, and FTP. It’s an essential tool for many developers, as it provides features such as bandwidth limiting, proxy support, user authentication, and more.
How to Install curl on Linux
In most Linux distributions, curl comes pre-installed. However, if you’re running a Linux version without curl or want an updated version, you can install it with these commands:
- Ubuntu/Debian:
sudo apt install curl
- RHEL-based (CentOS/Fedora):
sudo yum install curl
- Arch Linux:
sudo pacman -S curl
How to Use the curl Command
The curl command follows a simple syntax:
curl [options] url
Here are some useful examples of curl commands:
Download a file using curl
You can download a file from a specific URL with curl using the -O
flag. For example:
curl -O https://example.com/file.zip
Resume an interrupted download using curl
If a download is interrupted, you can use the -C -
flag to resume it with curl. For example:
curl -C -O https://example.com/file.zip
Download multiple files using curl
To download multiple files simultaneously via curl, you can use the -O
flag multiple times in the same command. For example:
curl -O https://example.com/file1.zip -O https://example.com/file2.zip
Get the HTTP headers of a web page
You can request the HTTP headers of a URL with the -I
(uppercase i, not L) and --http2
flags. For example:
curl -I --http2 https://example.com
Limit transfer rate with curl
You can limit the transfer rate of your downloads with the --limit-rate
flag followed by a modifier for kilobytes, megabytes, or gigabytes. For example:
curl --limit-rate 1m -O https://example.com/file.zip
Transfer files via FTP with curl
You can transfer files using the File Transfer Protocol (FTP) with curl by connecting to an FTP server and downloading or uploading files. Here are some example commands:
Connect to an FTP server:
curl -u username:password ftp://ftp.example.com/
Download a file from the FTP server:
curl -u username:password -O ftp://ftp.example.com/file.zip
Upload a file to the FTP server:
curl -T newfile.zip -u username:password ftp://ftp.example.com/
FAQs
1. What is curl?
Curl is a command-line utility used to transfer data to and from servers. It supports various protocols, including HTTP, HTTPS, SFTP, and FTP, and provides features like bandwidth limiting, proxy support, user authentication, and more.
2. How do I install curl on Linux?
Curl comes pre-installed on most Linux distributions, but you can install it with the appropriate package manager if it’s not already installed. For example, on Ubuntu or Debian, you can run sudo apt install curl
.
Final Thoughts
In summary, curl is a powerful command-line utility with various use-cases for downloading and uploading data from servers. With this guide, you should now have a better understanding of how to find and use the curl command in Linux.