Rewriting query string

[Olaf van der Spek]

> rewrite ^(.*)$ $1?ra=$remote_addr break;

The ra argument is inserted before the original query string. Is it possible
to append it to the original query string?
Is this behavior documented somewhere? Couldn't find it.
Can one also remove certain arguments from the query string this way?

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,286625,286625#msg-286625