curl

Download file

$ curl -O [https://example.com/file.zip]

$ curl -o [filename] [https://example.com/file]

$ curl -X POST -d ["key=value"] [https://api.example.com]

$ curl -L [https://example.com]

$ curl -H ["Content-Type: application/json"] -d ['{"key":"value"}'] [https://api.example.com]

$ curl -I [https://example.com]

curl [options] [URL...]

curl is a command-line tool for transferring data with URLs. It supports HTTP, HTTPS, FTP, and many other protocols, making it essential for web development, API testing, and file transfers.
The tool is ubiquitous in scripts, CI/CD pipelines, and system administration.

-O, --remote-name

Save with remote filename

Save to specified file

Follow redirects

HTTP method (GET, POST, PUT, DELETE)

Send POST data

Add custom header

Authentication

Fetch headers only

Verbose output

Silent mode

Fail silently on HTTP errors

Allow insecure SSL connections

Download file:

$ curl -O https://example.com/file.zip
curl -o myfile.zip https://example.com/download

$ # GET request
curl https://api.example.com/users

# POST JSON
curl -X POST \
  -H "Content-Type: application/json" \
  -d '{"name":"John","age":30}' \
  https://api.example.com/users

# With authentication
curl -u username:password https://api.example.com/data

$ # View response headers
curl -I https://example.com

# Custom headers
curl -H "Authorization: Bearer TOKEN" \
  https://api.example.com/secure

- Multiple protocols (HTTP, HTTPS, FTP, SFTP, etc.)
- Authentication (Basic, Digest, OAuth, etc.)
- Cookie support
- Proxy support
- SSL/TLS
- Rate limiting
- Resume transfers
- Multiple simultaneous transfers

Silent failures by default (use -f to change). Large downloads show progress by default (use -s for scripts). Cookie files need management. SSL certificate issues require -k (insecure). Complex syntax for advanced features.

curl was created by Daniel Stenberg in 1997 (originally httpget), becoming one of the most widely used command-line tools for data transfer.

wget(1), http(1), fetch(1)