Run a cron job every x seconds

As most of you know, the smallest time a cron job can be configured to run is every minute. To run a script every 15 seconds for example, you could use the following: main cron job: * * * * * /path/to/wrapper.sh wrapper.sh: /path/to/script & sleep 15 /path/to/script & sleep 15 /path/to/script & sleep 15 [...]