https

View documentation for the original command

$ tldr http

curl [options] <URL>

-o, --output
    Writes the output to a specified <file> instead of standard output.

-O, --remote-name
    Writes the output to a file named like the remote URL's filename.

-X, --request
    Specifies a custom request method to use (e.g., GET, POST, PUT, DELETE).

-d, --data
    Sends the specified data in a POST request. Useful for submitting form data to HTTPS endpoints.

-H, --header
    Passes a custom header to the server (e.g., 'Content-Type: application/json').

-u, --user
    Specifies user and password for server authentication over HTTPS.

-k, --insecure
    Allows curl to proceed insecurely and skip TLS/SSL certificate verification. Use with caution; primarily for debugging.

-L, --location
    Follows HTTP 3xx redirects automatically.

-v, --verbose
    Makes the operation more talkative, showing details like the TLS/SSL handshake process.

--cacert
    Uses the specified CA certificate file to verify the peer's certificate.

--cert
    Uses the specified client certificate file for client authentication.

--key
    Uses the specified private key file for client authentication.

--resolve
    Forces the host:port to resolve to the specified address. Useful for testing against specific IPs or internal hosts.

-I, --head
    Fetches the HTTP-header only (HEAD request), useful for checking HTTP status and headers without downloading content.

The term "https" refers to the Hypertext Transfer Protocol Secure, which is a protocol for secure communication over a computer network, widely used on the internet. It is not a Linux command itself. Instead, Linux systems provide various commands and utilities that utilize or interact with the HTTPS protocol. One of the most common and powerful command-line tools for making requests over HTTPS (among other protocols) is curl (Client for URLs).

curl is a robust utility designed for transferring data to or from a server using various protocols, including HTTP, HTTPS, FTP, and more. It is an indispensable tool for scripting network operations, testing web services, and debugging network connectivity, especially concerning secure (HTTPS) communication. It handles SSL/TLS handshakes, certificate validation, and encrypted data transmission, making it the de-facto choice for secure command-line web interactions.

While curl is incredibly powerful for HTTPS interactions:

• Using -k, --insecure disables critical security checks and should never be used in production environments, as it makes your connection vulnerable to man-in-the-middle attacks. It is strictly for development and debugging purposes.
• Passing sensitive information like passwords directly on the command line can expose them in shell history or process lists. Consider using environment variables or other secure methods.
• curl does not render HTML, execute JavaScript, or manage complex browser sessions (e.g., cookies and local storage persistence) like a web browser. It's a data transfer tool, not a headless browser.

curl natively supports the HTTPS protocol by integrating with SSL/TLS libraries (like OpenSSL or LibreSSL). This enables it to automatically handle the secure handshake, certificate validation, and encryption/decryption of data, making it a reliable tool for secure communication with web servers and APIs.

For debugging HTTPS connection problems, curl is invaluable. The -v (verbose) option provides detailed insights into the TLS/SSL handshake process, certificate exchange, and HTTP headers, which can help diagnose issues like certificate mismatches, handshake failures, or protocol errors. The -k (insecure) option is useful in controlled debugging environments where self-signed or invalid certificates might be encountered, allowing the connection to proceed despite certificate errors.

curl was originally released in 1997 as 'httpget', initially created to fetch currency exchange rates. It was renamed to curl in 1998. Over the years, it has evolved significantly, incorporating support for numerous protocols and features, making it one of the most widely used and versatile command-line tools for data transfer across the internet. Its consistent development, active community, and broad adoption have solidified its position as an indispensable utility for developers, system administrators, and anyone working with network protocols, especially HTTP/HTTPS.

wget(1), openssl(1), ss(8), netstat(8), httpie(1)