Introduction
	cURL is a command-line tool for transferring data to and from a server. It speaks a long list of protocols — HTTP, HTTPS, FTP, SFTP, and more — which makes it the standard way to fetch a URL, test an API, download a file, or check that your own web site is responding correctly, all without leaving the shell. cURL is closely related to Wget. The rule of thumb: reach for Wget when you want to download files (especially whole directories or recursive mirrors), and reach for cURL when you want to interact with a service — send data, set headers, follow an API conversation, or script a request and read the response.
	Installation
	cURL is so commonly used that it is often already present. Check with curl --version; if it is missing, connect to your VPS, become root, and install it: On FreeBSD 15: # pkg install curl On Rocky Linux 10: # dnf install curl
	Everyday Usage
	By default, cURL prints what it fetches to your terminal. The options you will use most often save it to a file, follow redirects, and show what is happening: $ curl https://example.com/ # print the page to the screen $ curl -O https://example.com/file.tar.gz # save as the remote file name $ curl -o site.html https://example.com/ # save under a name you choose $ curl -L https://example.com/ # -L follows redirects (http -> https, etc.) $ curl -I https://example.com/ # -I shows only the response headers To confirm your own site is up and serving the right thing — useful in a cron health check — combine -I (headers only) with -s (quiet) and -S (still show errors): $ curl -sS -I https://your-domain.example/
	Working with APIs
	Where cURL really earns its place is talking to web services. You can choose the request method, add headers, and send a body — everything a REST API needs: # A POST request with a JSON body and an auth header $ curl -X POST https://api.example.com/v1/items \ -H "Content-Type: application/json" \ -H "Authorization: Bearer YOUR_TOKEN" \ -d '{"name":"widget","qty":12}' Add -i to include the response headers in the output, or -v (verbose) to watch the whole exchange — the TLS handshake, the request headers cURL sent, and the response — which is the single most useful way to debug why a request is not behaving as expected. TIP: Avoid putting secrets such as API tokens directly on the command line — they are visible in your shell history and to anyone running ps. Read them from a file or an environment variable instead, for example -H "Authorization: Bearer $API_TOKEN" with the token exported in your shell.
	Documentation
	The curl(1) manual page lists every one of its many options. The project site has tutorials, a protocol-by-protocol guide, and a free book: cURL Documentation Everything cURL (the full manual, online)