Apache mod_rewrite RewriteRule

The following assumes that you have some idea of what you're doing and that you have $EnablePathInfo set. These rules are based on the CleanUrls recipe. Take note that you'll need to replace the text in bold with whatever's appropriate for your setup.

RewriteEngine On
# Define the rewrite base. This is the URL of the directory that the
# .htaccess file (if using) resides in
RewriteBase /url/path/to/rewrite/root
# Catch requests for index.anything
RewriteRule ^index  /  [R=301]

# Non-capital first letter means that it's not a wiki page
RewriteRule ^([a-z].*)$    $1  [L]


## Define the rules that exclude things from the cache:
# If any of these conditions are true ...

# Posting a form request
RewriteCond %{REQUEST_METHOD} POST          [OR]
# A session exists -> the user is signed in
RewriteCond %{HTTP_COOKIE}    PHPSESSID  [OR]
# A query string exists; ie. we're not just viewing a page
RewriteCond %{QUERY_STRING}   .

# ... serve the file using pmwiki.php
RewriteRule ^(.*)$            relative/url/path/to/pmwiki.php?n=$1  [QSA,L]


## We're this far in the script if it's ok to serve files from the cache

# Root means that we want the wiki homepage
RewriteCond %{REQUEST_URI}    ^/$
# Does the file exist?
# Change 'Main.HomePage' here if you're using a different page
RewriteCond /absolute/path/to/htmlcache/Main.HomePage.html  -f
# If so, serve it.
# Change 'Main.HomePage' here if you're using a different page
RewriteRule ^$  relative/url/path/to/htmlcache/Main.HomePage.html  [L]

# No . or / in the URL means that we want the group main page
RewriteCond %{REQUEST_URI}    ^/([^./?]+)[./]?$
# Does the file exist?
# Change '%1.%1' here if you're using a different group main page format
RewriteCond /absolute/path/to/htmlcache/%1.%1.html  -f
# If so, serve it.
RewriteRule ^([^./?]+)[./]?$  relative/url/path/to/htmlcache/$1.$1.html  [L]

# We want Group.Page
RewriteCond %{REQUEST_URI}    ^/([^./]+)[./]([^./]+)/?$
# Does the file exist?
RewriteCond /absolute/path/to/htmlcache/%1.%2.html  -f
# If so, serve it.
RewriteRule ^([^./]+)[./]([^./]+)/?$  relative/url/path/to/htmlcache/$1.$2.html  [L]


# Cache misses and anything that doesn't fit the above goes to pmwiki.php
RewriteRule ^(.*)$  relative/url/path/to/pmwiki.php?n=$1  [QSA,L]