In my own words, after reading the docs and experimenting:
You can use RewriteBase to provide a base for your rewrites. Consider this
# invoke rewrite engine
RewriteEngine On
RewriteBase /~new/
# add trailing slash if missing
rewriteRule ^(([a-z0-9\-]+/)*[a-z0-9\-]+)$ $1/ [NC,R=301,L]
This is a real rule I use to ensure that URLs have a trailing slash. IMO, it looks neater. This will convert