You may customize the way tests are executed to suite your needs. You can even change the language of execution!
The is done by defining any of a few special variables in the scope (see VariableScope) of the tests you wish to execute.
The special variables are:

• COMMAND_PATTERN
• TEST_RUNNER
• PATH_SEPARATOR

COMMAND_PATTERN is the basis for every execution performed in FitNesse. It specifies the command that will be executed.
default: java -cp %p %m
There are two special symbols used that will get replaced before execution.

• %p will be replaces with the caclulated path/classpath. This is the accumulation of all the !path elements on all the ClassPath pages in the scope of the current page.
• %m stands for main or main class. For Java it is the name of the class that will be executed.

TEST_RUNNER is the name of the class or executable that will be used when the Test button is clicked.
default: fit.FitServer
If you're running tests in Java you probably don't want to change this.

PATH_SEPARATOR is the charater that is used to separate all the path elements in the calculated path.
default: system dependant.... either ; or :