Apache and PHP are pre-installed on Mac OS X client, but disabled by default. The following should work for Leopard (10.5.x), Tiger (10.4.x) and Panther (10.3.x) client (if there is no previous version of DokuWiki installed). For Lion/Mountain Lion (10.7.x/10.8.x), the Sites folder no longer exists. These instructions revive it. Then follow the instructions below skipping step 4.

1. Enable PHP in Apache and Allow Directory Accesses
   1. Backup httpd.conf:

      $ sudo cp /private/etc/apache2/httpd.conf /private/etc/apache2/httpd.conf.bak

   2. Edit httpd.conf:

      $ sudo pico /private/etc/apache2/httpd.conf

   3. Make the following changes to httpd.conf:
      • CHANGE:

        #LoadModule php5_module

      • TO:

        LoadModule php5_module 

2. Download dokuwiki-yyyy-mm-dd.tgz (assuming to ~/Downloads)
3. Unpack downloaded file, move to appropriate location, and change ownership:

   $ cd ~/Downloads && tar -zxvf dokuwiki-yyyy-mm-dd.tgz
   $ mv dokuwiki-yyyy-mm-dd ~/Sites/dokuwiki
   $ cd ~/Sites/dokuwiki
   $ sudo chown -R www data conf lib/plugins

4. Start Personal Web Sharing in System Preferences → Sharing

You should now be able to run the installer at http://localhost/~your_username/dokuwiki/install.php

EDIT: since OSX Mountain Lion, the simple “Web Sharing” Option is no longer the way to start the Apache. Please follow the following link to get Apache run under OSX Mountain Lion:

http://osxdaily.com/2012/09/02/start-apache-web-server-mac-os-x/

For Tiger (10.4.x) and Panther (10.3.x) server:

1. Mac OS Server has Apache and PHP pre-installed; they are enabled through the Server Admin application. Enable “php4_module” under Web → Modules, and start (or restart) and configure the web service.
2. Download dokuwiki-yyyy-mm-dd.tgz (assuming to ~/Desktop)
3. From the command line:

   $ cd ~/Desktop && tar -zxvf dokuwiki-yyyy-mm-dd.tgz
   $ mv dokuwiki-yyyy-mm-dd ~/Sites/dokuwiki
   $ cd ~/Sites/dokuwiki
   $ sudo chown -R www data conf

You should now be able to run the installer at http://localhost/dokuwiki/install.php