It will execute it again, unless you take steps yourself to prevent more than one instance running. You can test it by running a script that does:
date >> /tmp/a
sleep 90
date >> /tmp/a
Question
What does Unix Kernel do if cron job set for every minute is executing a file which takes time more than 1 minute.
For Example:
I have following Shell Command to execute PHP Script every minute.
* * * * * php /home/user/public_html/script.php
And My PHP script consists SQL code to select emails from database and send mails to given Emails using for loop.
Problem: How the system kernel will response if my database consists thousands of mail which takes more than 1 minute to finish the 1st execution.
No correct solution
OTHER TIPS
It will execute it again, unless you take steps yourself to prevent more than one instance running. You can test it by running a script that does:
date >> /tmp/a
sleep 90
date >> /tmp/a
You have 2 options:
We often use option two and simply write a lock flag to the DB or to the filesystem - and then clear it once the script has completed.