clever grep..

Hello,

"Nicely reengineering" my webserver settings I got into
a mistake filling the nginx conf of my personal website,
that likely last for one nice day..only:

http://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.orghttp://mydeeds.org...

Angry with myself for this kind of error:

server {
listen 80;
listen [::]:80;

access_log off;

return 301 $host$request_uri
}

And interested to check for the possibility of a reiterated mistake I
launched in my conf repo:

grep "return 301 $host$request_uri" *.conf

getting a nice formatted list of all my redirects, one by one, to SSL
like exactly set for all my websites, in the form:

return 301 https://5mode.com/hello.html;

The result is the same both live under Linux and in my OpenBSD.
Checked doc without luck..

Could you eventually explain me the grep behavior here and how/if $host
and $requeste_uri get expanded like it appears?

Thanks!

-Dan