How to Use cURL to Download Files: Comprehensive Guide

View the full response

This shows detailed request and response information, including the status code and the target URL for redirection.

curl -v https://example.com

Using the -L option to handle redirects

curl -L https://example.com

Automatically handling redirects and downloading the file

You can combine the -L option and the -O (save file) option, so that when a file is redirected, cURL will automatically download the file.
The -O option saves the downloaded file with its original filename.

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

Rate Limiting

url --limit-rate 100k -O https://example.com/file.zip

The –limit-rate 100k option limits the download speed to 100KB/s.

Silent Download

A silent download typically refers to downloading a file without displaying any output such as progress bars, error messages, or other log data. It’s commonly used for automation scripts, background tasks, or when you don’t want to disrupt the user.

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

The -s or –silent flag enables silent mode, meaning no progress bars, error messages, etc., will be shown.
The -O option saves the file with the same name as the URL.

Authentication

Basic authentication is the most common HTTP authentication method, which typically requires a username and password. The server verifies these credentials to confirm the request’s legitimacy.

curl -u username:password -O https://example.com/protectedfile.zip

The -u username: password option is used to provide the username and password.
The -O option saves the file with the same name as the URL.

Using cURL with Proxy Servers

At Thordata, we work with proxies every day, and cURL is one of our go-to tools for testing and using them. Many of our customers route traffic through proxies for security, logging, or geo-routing, and cURL integrates cleanly with both HTTP and SOCKS proxies, including authenticated ones.

To send cURL traffic through a proxy, we use the `-x` (or `--proxy`) option:

curl -x http://proxy.example.com:8080 -L -O https://example.com/file.zip

For SOCKS proxies:

curl -x socks5://127.0.0.1:9050 -L -O https://example.com/file.zip

When a proxy requires authentication, we often test it like this:

curl -x http://username:password@thordata.net:8080 -L -O https://example.com/file.zip

In longer-term setups, we prefer environment variables such as HTTP_PROXY, HTTPS_PROXY, and NO_PROXY so we do not have to repeat proxy settings in every command. Whether we are using cURL with our residential or ISP proxies, we always remind customers to follow all applicable terms of service, network policies, and legal requirements.

Advanced Operations with cURL Command for Downloading Files

Resuming Downloads

When a file download is interrupted, you can use cURL to resume downloading.

curl -C - -O https://example.com/largefile.zip

The -C – option tells cURL to continue downloading the file from where it was interrupted, and the -O option saves the file with its original filename.

Downloading Multiple Files

You can download multiple files by calling curl multiple times, or by placing multiple file URLs in a text file.

Method 1: Calling curl multiple times

curl -O https://thordata.com/file1.zip

curl -O https://thordata.com/file2.zip

Method 2: Place multiple file URLs in a text file and use xargs

echo -e "https://example.com/file1.zip\nhttps://thordata.com/file2.zip" | xargs -n 1 -P 2 curl -O

Displaying the Download Progress Bar

By default, cURL displays a progress bar showing the download progress. If you need more detailed progress information (such as download speed, size, etc.), you can use the –progress-bar flag:

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

Common cURL Command Examples

For more cURL command-line options, check the manual: cURL Manual

Differences between cURL and wget

Both cURL and wget can be used to download files, but they have some differences.

Functionality: cURL excels at handling various HTTP request types (e.g., GET, POST). Wget primarily focuses on downloading files from the internet.

Command Parameters: cURL requires the -o parameter to specify a file for downloading, whereas wget does not require parameters to download a file directly.

For simple one-off file downloads, both tools can be used. However, for complex data exchange tasks, cURL is usually recommended. For downloading large, static resources efficiently, wget may be a better choice.

Common Errors and Best Practices

Not Handling Redirects: Failing to handle HTTP redirects during file downloads can cause downloads to fail, especially if the target URL has changed. The best practice is to use -L to redirect cURL to the target site.

Not Using -O or -o to Specify Filenames: This can lead to cURL saving files with default names instead of custom ones.

Not Handling Failures or Errors: If the server returns a 404 error or other failures, cURL will continue attempting to access the error message. The correct approach is to use -f to stop the download when cURL encounters an error.

Not Considering Bandwidth Limitation for Large Files: For large file downloads, setting an appropriate bandwidth limit can prevent disruption to other network activities. Use the –limit-rate option to control download speed.

Conclusion

Using cURL to download files provides a powerful, scriptable, and cross-platform approach to retrieving data from the web and internal services. By understanding core options like `-o`, `-O`, `-L`, `-C -`, and `--retry`, technical users can handle everything from simple one-off downloads to complex, authenticated, and automated retrieval tasks.

Through this guide, you’ll learn how to manage filenames, handle redirects, perform authentication, limit download speed, and avoid common errors.

 

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Yulia

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Yulia is a dynamic content manager with extensive experience in social media, project management, and SEO content marketing. She is passionate about exploring new trends in technology and cybersecurity, especially in data privacy and encryption. In her free time, she enjoys relaxing with yoga and trying new dishes.