Unfortunately, it is not possible to run a cron job every 2 minutes and 30 seconds as the cron daemon only supports scheduling at the level of minutes.
One way to achieve this would be to schedule a cron job to run every 2 minutes, and then within the script that the cron job runs, include additional logic to only execute the desired task every 2 minutes and 30 seconds.
For example, you can use the following cron expression to run a script every 2 minutes:
*/2 * * * * /path/to/script.sh
And then within the script, you can use the sleep command to pause the script for 30 seconds before executing the task.
#!/bin/bash
# wait for 30 seconds
sleep 30s
# execute task
command-to-be-executed
This way you can run a task every 2 minutes and 30 seconds.