mod_rewrite for MediaWiki

In moving the X-Plane SDK Wiki to MediaWiki I had to use mod_rewrite. Getting this right took me a few tries.  This is what I ended up with:
# First: any old phpwiki witih a query is rewritten to the
# "clean" mediawiki URL. Note that we do not test for file
# existence - as of this writing the php index.php DOES exist.

RewriteCond %{QUERY_STRING} ^(.+)$
RewriteRule ^xpsdk/phpwiki/(.*)$ /xpsdk/mediawiki/%1? [R=301]

# Also, if we did not rewrite that means we had no query -
# means the default page - map it to the base root.

RewriteRule ^xpsdk/phpwiki/(.*)$ /xpsdk/mediawiki/ [R=301]

# Now we have "clean" wiki URLs, so do not make any more rewrites
# permanent. What we do next is to clean up problems.

# And finally and most importantly: because php is running in a CGI,
# it needs the "ugly" title=$1 form. So...convert the virtual path
# into CGI access.

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^xpsdk/mediawiki/(.+)$ /xpsdk/mediawiki/index.php?title=$1 [L,QSA]Probably the most useful thing I discovered was: by using R=301 you can force the rewrite to be visible in the URL bar. This isn't always what you want in the long term, but it does let you see the output of mod_rewrite, which is handy.