Downloading Files with cURL: A Guide to Data Transfer from the Command Line
💡 What Will You Learn in This Guide?
In this guide, you will learn how to download files from the command line using the cURL (Client URL) tool.
You'll discover step by step how to save files with different names, follow directions, add authentication, and automate downloads.
You'll also learn when you should opt for alternatives like wget.
⚙️ Technical Summary
Main Technical Topic: Downloading Files and Transferring Data with the cURL Command Line Tool
Problem it solves: It makes file downloading and data transfer fast, secure and automation-friendly in Linux and API environments.
Steps:
- Bringing the file to the terminal
- Save the file with the same or different name
- Monitor HTTP redirects
- Download with authentication
- Resume download and try again
- Evaluating wget alternative
🧩 Step 1: Receiving and Viewing the Remote File
By default curl writes the contents of the file at the given URL to the terminal screen.
curl https://www.ornek.com/robots.txt
This command fetches the target file and prints its contents to the screen.
Sample output:
User-agent: *
Disallow: /wp-admin/
Allow: /wp-admin/admin-ajax.php
Sitemap: https://www.ornek.com/sitemap.xml
💾 Step 2: Saving the File with the Same Name
Use the -O (capital O) flag to save the file to the local disk instead of the terminal.
curl -O https://www.ornek.com/robots.txt
This script saves the file locally with the same name as on the server.
Once the download is complete, check the content:
cat robots.txt
✏️ Step 3: Saving the File with a Different Name
If you want to prevent existing files from being overwritten or give them a special name, use the -o (lowercase o) flag.
curl -o rb-botlar.txt https://www.ornek.com/robots.txt
This command saves the file with the name rb-botlar.txt.
To check after download:
cat rb-botlar.txt
🔄 Step 4: Follow Redirects
Some web servers redirect HTTP requests to HTTPS. By default curl does not follow these redirects.
To see only header information:
curl -I http://www.ornek.com/robots.txt
To track redirects automatically:
curl -L https://www.ornek.com/robots.txt
The -L (location) flag allows cURL to automatically follow redirects.
Both follow the redirect and save:
curl -L -o rb-botlar.txt http://www.ornek.com/robots.txt
🔐 Step 5: Download Files with Authentication
Some files or API endpoints require authentication for access.
🧾 Basic Auth
curl -u kullanici:parola -O https://api.ornek.com/guvenli-dosya.zip
🔑 Token Based Authentication
curl -H "Authorization: Bearer $API_TOKEN" -O https://api.ornek.com/korumali-veri.json
Store password and token information in environment variables instead of writing them directly into the command.
⚙️ Step 6: Advanced Download Control
🔁 Resuming an Interrupted Download
curl -C - -O https://veriseti.ornek.com/buyukdosya.iso
If the download is interrupted, this command continues where it left off.
🕒 Setting Timeout
curl --max-time 30 -O https://example.com/file.txt
If no response is received within 30 seconds, the transaction is terminated.
🔁 Automatic Retry
curl --retry 3 -O https://api.ornek.com/paket.tgz
It automatically tries unsuccessful downloads three times.
⚡ Step 7: wget Alternative
wget is especially advantageous when downloading websites or multiple files.
| Use Case | Command | Description |
|---|---|---|
| Single file download | wget https://example.com/file.zip | Simple download |
| Background download | wget -b URL | It continues to download even if you close the terminal |
| Setting a speed limit | wget --limit-rate=300k URL | To limit bandwidth |
| Site mirroring | wget --mirror URL | Downloads the entire site |
When wget?
-
If you want to download websites completely
-
If automatic retry is required
When cURL?
-
If you work with APIs
-
Header or authentication required
-
If you use it in automation scripts
🧠 Frequently Asked Questions (FAQ)
1. What is the difference between -o and -o?
-O saves the file with its original name, -o lets you save it with a custom name.
2. Does cURL work on Windows?
Yes, it is available by default in Windows 10+. It can be used with PowerShell or Git Bash.
3. Why doesn't it follow the directions?
curl does not follow redirects when the -L parameter is not added.
4. I'm getting an SSL error, what should I do?
The curl -k parameter bypasses the certificate check, but is not recommended for security reasons.
5. wget or cURL?
wget is better suited for file downloading, while cURL is better suited for API and automation.
🎯 Result
cURL is the most used command line data transfer tool for both system administrators and developers. It offers a powerful networking tool with download, referral tracking, authentication, and automation support.
🚀 Now try what you've learned in the GenixNode environment and automate your data transfer processes.