Create a file at time 't' after PBS job execution begins

I submit a PBS job for 02:00:00 hours. I need to create a file in the PBS working directory at a specified time ***t*** (say 01:30:00 hours) after the job has begun to ensure that the job terminates smoothly for any subsequent restart. For example something as follows echo "LABORT" > file1.txt I do not want to rely on PBS for the file creation through chaining jobs, since I want to create it exactly at the specified time. Is there a clean and automated way to achieve this while running many such jobs? EDIT 1: I believe crontab can perform the task, but how to perform the following - monitor the jobs under a given username, - get the job start time and working directory - Add the time t to start time and Pass the modified - time and working directory to crontab