Bukkit

Your plugin could create an empty file that can be tested against in the batch/shell script to determine if it should restart the server, eliminating the need to issue a break to stop the script loop.

During your on enable, check if the flag file exists from a previous restart.  If so delete the file.

When the schedule time to restart the server is reached, create the flag file and stop the server.

If a stop command is issued to the server, your plugin should just shutdown normally without creating the file.

The batch/shell script can use an if statement to test if the file exists.  If the file exists it loops, if not it exits.

For Batch something like
:DoRestart
  Java –jar craftbukkit.jar
IF EXIST C:\Bukkit\restart.flag GOTO DoRestart

For Bash
while [ -f /bukkit/restart.flag ] ;
do
  java –jar craftbukkit.jar
done

or for bash you could use an infinite loop with an if statement that calls the break command.

I like the idea, and will most likely include it in the next update, thanks