Linux Crontab Timing task execution in seconds

 

The smallest unit of execution time in the crontab minutes.

If you need to execute in seconds, there are two ways:

 

Method One: be achieved through sleep

Example:

1, create a test.php file, here are distinguished by good test printing time.

<?php
    file_put_contents('log.txt',date('Y-m-d H:i:s') . "\n", FILE_APPEND);
?>

2, to ensure that individual access test.php file to print the log.

3, edit the crontab file, the crontab -e command, for example, I want to run every 15 seconds, as follows:

* * * * * curl "http://127.0.0.1/testtask/test.php" && sleep 15;curl "http://127.0.0.1/testtask/test.php" && sleep 15;curl "http://127.0.0.1/testtask/test.php" && sleep 15;curl "http://127.0.0.1/testtask/test.php"

4, print the results, you can see the results in real time through the tail -f log.txt command.

It can be seen every 15 seconds to print out the results.

 

 

Method Two: be accomplished by adding an intermediate shell scripts

Example:

1, add a script file test.sh, reads as follows: I am here is to choose two seconds once.

step=2 #间隔秒数
for ((i = 0; i < 60; i = (i + step))); do
    $(curl "http://127.0.0.1/testtask/test.php")
    sleep $step
done
exit 0

2, edit the crontab file

* * * * * /phpstudy/www/testtask/test.sh

3, print results