The Regular Expression translates to: “rewrite all URLs without any ‘.’ (dot) in them that don’t end with a ‘/’ to the URI + ‘/'” Or simply: “If the URI doesn’t have a period and does not end with a slash, add a slash to the end”.
rewrite ^([^.]*[^/])$ $1/ permanent;
This very simply rewrites all URI’s that don’t have periods in them to your index.php (or whatever file you would execute your controller from).
rewrite ^([^.]*)$ /index.php;