Linux uses the Cron+at implementation to randomly execute commands within a certain time period _linux

Write a script to sign in, but do not want to always in the time to check in the database, otherwise the record in the data base is too fake, so you need to determine the time period, randomly selected time to execute, finally thought of using CRON+AT implementation

The simple idea is that Cron sets a starting time, like 6 a day in the morning, and a random 2-350 minutes later to sign in.

So as long as this

0 6 * * * echo ' sleep ' $ (shuf-i 1-60-n 1) ';d ate >>/tmp/xxxx.txt ' |at now + $ (shuf-i 2-350-n 1) min

The reason why we have a random 1-60 second sleep is because at is the whole point of execution, do not want to have the database only the entire minutes of the check-in record.

This saves a lot of resources than the way to sleep directly in cron, and the maximum dwell time is no more than 60 seconds.

To keep the simplicity in cron, you can then wrap a script