cURL manpage
URL
Uniform resource locator
Client
The machine requesting a resource from a "server"
Example of a GET request
$ curl https://tilde.club/
cURL guesses the protocol even when you supply the domain/address
$ curl raspbian.raspberrypi.org/multiarch/db/packages.db.mirrorlist
Output
--snip--
* using HTTP/1.x
--snip--
$ curl ftp.acc.umu.se/mirror/raspbian/
Output
--snip--
* [FTP] [STOP] -> [WAIT220]
--snip--
Redirecting cURL output to a file
$ curl ftp.acc.umu.se/mirror/raspbian/ --output index.html
$ curl ftp.acc.umu.se/mirror/raspbian/ -o index.html
$ curl ftp.acc.umu.se/mirror/raspbian/ > index.html