Query_vars not working for me

Question

I'm trying to add an all pages link to posts when I have ?all=1 at the end of the URL it's returning "not set", I'm not sure what I'm doing wrong. I've looked here and my code is the same as here: http://codex.wordpress.org/Custom_Queries#Custom_Archives

functions.php

add_filter('query_vars', 'all_pages' );
function all_pages( $qvars ) {
$qvars[] = 'all';
return $qvars;
}

single.php

global $wp_query;
if (isset($wp_query->query_vars['all'])) {
    $remove_pagination = $wp_query->query_vars['all']; 
    echo "all set";

} else { echo "not set"; };

Answer 1

My issue was with nginx, specifically:

location / {
   index index.php index.html;
   try_files $uri $uri/ /index.php;
}

Which I changed try_files $uri $uri/ /index.php; to try_files $uri $uri/ /index.php?$args; as outlined here which also fixed another issue that I was having with URL parameters.