Running a cron every 30 seconds

Question

Ok so I have a cron that I need to run every 30 seconds.

Here is what I have:

*/30 * * * * /bin/bash -l -c \'cd /srv/last_song/releases/2012030813315         


        

Answer 1

Crontab job can be used to schedule a job in minutes/hours/days, but not in seconds. The alternative :

Create a script to execute every 30 seconds:

#!/bin/bash
# 30sec.sh

for COUNT in `seq 29` ; do
  cp /application/tmp/* /home/test
  sleep 30
done

Use crontab -e and a crontab to execute this script:

* * * * * /home/test/30sec.sh > /dev/null