CentOS - May 2013 - Shell Scripting Random Delay

I have a shell script that's run every 5 minutes I use to call many
other shell scripts.  Is there a way to wait a random number of
seconds before executing each line?  Something like this.

wait_random 10 - 180 (perl /scripts/my_script.pl) &
wait_random 10 - 180 (perl /scripts/my_script5.pl) &
wait_random 10 - 180 (perl /scripts/my_script7.pl) &

I have many entries in this file and I background them all because
most must poll network devices which can take time.  None should take
over 2 minutes though.

When I run them all at once they bog the system and cause some of
latency graphs on equipment being monitored to look poor.

On Wed, May 15, 2013 at 11:44 AM, Matt <matt.mailinglists at gmail.com>
wrote:
> I have a shell script that's run every 5 minutes I use to call many
> other shell scripts.  Is there a way to wait a random number of
> seconds before executing each line?  Something like this.
>
Use your script to generate a random number [0] and pass that to the sleep
command?

[0] http://islandlinux.org/howto/generate-random-numbers-bash-scripting

> wait_random 10 - 180 (perl /scripts/my_script.pl) &
> wait_random 10 - 180 (perl /scripts/my_script5.pl) &
> wait_random 10 - 180 (perl /scripts/my_script7.pl) &
>
> I have many entries in this file and I background them all because
> most must poll network devices which can take time.  None should take
> over 2 minutes though.
>
> When I run them all at once they bog the system and cause some of
> latency graphs on equipment being monitored to look poor.
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos
>


-- 
---~~.~~---
Mike
//  SilverTip257  //

Something like

sleep  $(($(date +%S)*3))

More random would be to use nanoseconds (see date manpage), but then 
you'd have to cook up an algorithm to test and toss out values 
(arguments to 'sleep') which you didn't want.

On 05/15/2013 11:44 AM Matt wrote:
> I have a shell script that's run every 5 minutes I use to call many
> other shell scripts.  Is there a way to wait a random number of
> seconds before executing each line?  Something like this.
>
> wait_random 10 - 180 (perl /scripts/my_script.pl) &
> wait_random 10 - 180 (perl /scripts/my_script5.pl) &
> wait_random 10 - 180 (perl /scripts/my_script7.pl) &
>
> I have many entries in this file and I background them all because
> most must poll network devices which can take time.  None should take
> over 2 minutes though.
>
> When I run them all at once they bog the system and cause some of
> latency graphs on equipment being monitored to look poor.
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos
>

Matt wrote:
> I have a shell script that's run every 5 minutes I use to call many
> other shell scripts.  Is there a way to wait a random number of
> seconds before executing each line?  Something like this.
>
> wait_random 10 - 180 (perl /scripts/my_script.pl) &
> wait_random 10 - 180 (perl /scripts/my_script5.pl) &
> wait_random 10 - 180 (perl /scripts/my_script7.pl) &
>
> I have many entries in this file and I background them all because
> most must poll network devices which can take time.  None should take
> over 2 minutes though.
>
> When I run them all at once they bog the system and cause some of
> latency graphs on equipment being monitored to look poor.
There's a better answer: do some testing to find out just how many you can
do at a time without the network bogging down, then
for ( $list <space separated line of file with devices> ) {
    my_script.pl $list
}

With the datafile being something like
#fast device responders
dev1 dev2 dev3 dev4
dev5 dev6 dev7 dev8
#slow device responders
sdev1 sdev2
sdev3 sdev4

And make your script do all of the first line, then wait for responses.

       mark

On 2013-05-15 17:44, Matt wrote:
> I have a shell script that's run every 5 minutes I use to call many
> other shell scripts.  Is there a way to wait a random number of
> seconds before executing each line?  Something like this.
>
> wait_random 10 - 180 (perl /scripts/my_script.pl) &
> wait_random 10 - 180 (perl /scripts/my_script5.pl) &
> wait_random 10 - 180 (perl /scripts/my_script7.pl) &
>
> I have many entries in this file and I background them all because
> most must poll network devices which can take time.  None should take
> over 2 minutes though.
>
> When I run them all at once they bog the system and cause some of
> latency graphs on equipment being monitored to look poor.
Wait randomized interval of 60 seconds and start

   perl -e "sleep(int(rand(60)))" && (perl
/scripts/my_script.pl)

Am 15.05.2013 um 17:44 schrieb Matt <matt.mailinglists at
gmail.com>:
> I have a shell script that's run every 5 minutes I use to call many
> other shell scripts.  Is there a way to wait a random number of
> seconds before executing each line?  Something like this.
> 
> wait_random 10 - 180 (perl /scripts/my_script.pl) &
> wait_random 10 - 180 (perl /scripts/my_script5.pl) &
> wait_random 10 - 180 (perl /scripts/my_script7.pl) &
> 
> I have many entries in this file and I background them all because
> most must poll network devices which can take time.  None should take
> over 2 minutes though.
> 
> When I run them all at once they bog the system and cause some of
> latency graphs on equipment being monitored to look poor.

for bash scripts:

MOD="45"
sleep "$[($RANDOM % $MOD)]"

# RANDOM Each time this parameter is referenced, a random integer between 0 and
32767 is generated.
# sleep will wait something beetween 0 and 45 seconds 

--
LF