Simple C website to print out all env variables:

#include "stdio.h"

int main(int argc, char **argv, char **env){

        printf("Content-Type: text/html; charset=utf-8\r\n\r\n");

        while(*env){
                printf("%s<br>", *env);
                env += 1;
        }
}


What i get as output when i view this website in a browser:

HTTPS=on
SSL_TLS_SNI=XXXXX
HTTP_HOST=XXXXX
HTTP_CONNECTION=keep-alive
HTTP_CACHE_CONTROL=max-age=0
HTTP_UPGRADE_INSECURE_REQUESTS=1
HTTP_USER_AGENT=Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) QtWebEngine/5.15.10 Chrome/87.0.4280.144 Safari/537.36
HTTP_ACCEPT=text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
HTTP_DNT=1
HTTP_ACCEPT_LANGUAGE=en-US,en;q=0.9
HTTP_SEC_FETCH_SITE=none
HTTP_SEC_FETCH_MODE=navigate
HTTP_SEC_FETCH_USER=?1
HTTP_SEC_FETCH_DEST=document
HTTP_ACCEPT_ENCODING=gzip, deflate, br
HTTP_COOKIE=__guid=187019561.2921955125866414600.1685533830264.0325
PATH=/usr/local/sbin:/usr/local/bin:/usr/bin
SERVER_SIGNATURE=
SERVER_SOFTWARE=Apache/2.4.57 (Unix) OpenSSL/3.1.1 PHP/8.2.8
SERVER_NAME=XXXXX
SERVER_ADDR=192.168.31.110
SERVER_PORT=443
REMOTE_ADDR=192.168.31.1
DOCUMENT_ROOT=/srv/http/
REQUEST_SCHEME=https
CONTEXT_PREFIX=/cgi-bin/
CONTEXT_DOCUMENT_ROOT=/srv/http/cgi-bin/
SERVER_ADMIN=XXXXX
SCRIPT_FILENAME=/srv/http/cgi-bin/a.out
REMOTE_PORT=37400
GATEWAY_INTERFACE=CGI/1.1
SERVER_PROTOCOL=HTTP/1.1
REQUEST_METHOD=GET
QUERY_STRING=
REQUEST_URI=/cgi-bin/a.out
SCRIPT_NAME=/cgi-bin/a.out