The fitnesse-git-plugin is intended to work with FitNesse's built-in Source Control mechanism.
To use it, add CM_SYSTEM as an environment variable or a defined variable in FitNesse.

Please see http://www.fitnesse.org/FitNesse.UserGuide.AdministeringFitNesse.SourceCodeControl

Put the fitnesse-git-plugin.jar in a folder called "plugins" next to the fitnesse.jar
  |---fitnesse.jar
  |---plugins
  |------fitnesse-git-plugin.jar
  |---plugins.properties
  |---run.sh
  |---run.bat

Add git.path=/your/path/to/git to plugins.properties
Example of plugins.properties
  ---------------------------------------------
  |git.path=git.path=/your/path/to/git
  ---------------------------------------------

Example of run.sh (OSX)
  ---------------------------------------------
  |export CM_SYSTEM=org.fitnesse.plugins.GitScm
  |java -jar fitnesse.jar -e 0 -p 9001
  ---------------------------------------------

Example of run.bat (Windows)
  ---------------------------------------------
  |set CM_SYSTEM=org.fitnesse.plugins.GitScm
  |java -jar fitnesse.jar -e 0 -p 9001
  ---------------------------------------------

To test it, try making changes to a FitNesse page and check your git log to see if it committed

Feedback is appreciated!


***Known Problem***
Doesn't work on OSX because of the StringTokenization with Runtime.getRuntime.exec(String command)
I think the fitnesse.components.CommandRunner needs to be changed to explicitely call "rt.exec(new String[]{command}, environmentVariables);"
Here's what I found:
  http://stackoverflow.com/questions/161859/using-quotes-within-getruntime-exec
  http://www.velocityreviews.com/forums/t138173-runtime-getruntim-exec-somecmd-problem-with-linux.html