crontask | call scripts or URLs from a crontab file | Cron Utils library

I'm looking for a way to lazily compose two effects without first executing their results in Zio. My program takes the following form:

I want to have a crontask that executes every minute. However in plesk you can only set a crontask every hour and the minute to execute it.

You can however choose to do this with a workaround. From the Plesk manual I found : https://support.plesk.com/hc/en-us/articles/115004281794-How-to-create-a-scheduled-task-to-fetch-URL-every-15-seconds

And they noted the following code :

for i in {1..4}; do curl --silent "http://example.com" &>/dev/null; sleep 15; done

However I am a bit afraid of using this code. My guess to make a script execute every minute would be like:

for i in {1..4}; do curl --silent "http://example.com/myscript.php" &>/dev/null; sleep 60; done

But what scares me a bit is : /dev/null I am not a unix guru at all but to my knowing /dev/null is the trashbin.

And what does 1..4 do? Looks to me like it repeats itself only 4 times?

Lets say I have crontask.py that reads from a list of services running on AWS and spawns new metrics threads for each service to go out and grab the CPUUtilization for their respective auto scaling groups and perform some threshold calculations. This was working fine previously when I used the usual: