The Referer field in the HTTP header identifies the page that led to the current web page. When a user clicks on a link on web page A to go to web page B, the referer header string for page B will contain the URL of page A.
Some dynamic pages check the referer string before returning the HTML data. For example, a web page may display a Google logo when a user navigates to a website from Google, and display a different page when the user types the URL.
A web developer can write a condition to return a Google page if the referer is www.google.com, or return a different page if not.
You can use --referer with the curl command to specify the referer string, as follows:
$ curl --referer Referer_URL target_URL ...
