Crontab schedule issue - cron

Question

I have several scripts that are run every 3 minutes and schedule looks like this:
*/3 * * * * /some/script1.php
*/3 * * * * /some/script2.php
*/3 * * * * /some/script3.php
I suppose that these scripts run at the same time, but I wish that these scripts run every 3 minute but not in the same time. Tell me please how can I reach this.

Answer 1

You can't reach that with the lines you are having, those will allways be running at the same times. However, you can simply create one "master" script that gets called via cron and then calls the scripts one after the other.
*/3 * * * * /usr/bin/php /some/masterscript.php
masterscript.php:
<?php
exec('/usr/bin/php /some/script1.php');
exec('/usr/bin/php /some/script2.php');
exec('/usr/bin/php /some/script3.php');
?>
EDIT:
Depending on your server's setup - install node.js. There's a cron package you can set for every second. Maybe this can help..

Answer 2

You can but not with that syntax, instead you should use this kind of syntax:
1,4,7,10,13,16,etc... * * * * /some/script1.php
2,5,8,11,14,17,etc... * * * * /some/script2.php
and so on....

Answer 3

If you just want each script to execute in turn, with the second not starting until the first has finished, and so forth, just put them all in a single cron command.
cron invokes each command by passing the command string to /bin/sh -- and the shell can very easily invoke several commands in sequence.
*/3 * * * * /some/script1.php ; /some/script2.php ; /some/script3.php

Answer 4

do you think a couple of seconds between scripts run could be enough ?
what about a command like this ?
*/3 * * * * echo "<?php echo 'Start ...';sleep(2);echo Go; ?>"|php /some/script1.php
*/3 * * * * echo "<?php echo 'Start ...';sleep(4);echo Go; ?>"|php /some/script2.php
*/3 * * * * echo "<?php echo 'Start ...';sleep(6);echo Go; ?>"|php /some/script3.php
You could also substitute fixed waiting time with random waiting time.
Instead of sleep(2) try a generic sleep(rand(1,10)).
I hope this could be useful