Send an HTTP request to the website example.com using the User-Agent string "Mozilla/5.0 (X11; Linux x86_64; rv:80.0) Gecko/20100101 Firefox/80.0" with the command line tool curl.
curl -H 'User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:80.0) Gecko/20100101 Firefox/80.0' http://example.com