Apache and mod_rewrite

If you're getting errors like this in Apache:

.htaccess: Invalid command 'RewriteEngine', perhaps misspelled or defined by a module not included in the server configuration

that probably means you don't have mod_rewrite enabled. You can enable it easily enough by using the "a2enmod" tool. On Ubuntu, like this:

$ sudo a2enmod rewrite


and then restarting apache, of course.