Cron Job

You can write a script that used lsof to track if you script file is in use, or ps to track if an application is running, then choose the appropriate actions based upon the results.

The code below can be used as a base to track if a file is in use and you can adjust the conditional criteria to fit your needs.

#!/bin/bash                                                                                                                                                                                    
                                                                                                                                                                                               
SCRIPT="testscript.sh"                                                                                                                                                                               
                                                                                                                                                                                               
if [ -n "$(lsof|grep -i $SCRIPT)" ]; then                                                                                                                                                      
        echo "$SCRIPT is running"                                                                                                                                                              
else                                                                                                                                                                                           
        echo "$SCRIPT is not running"                                                                                                                                                          
fi