Re : How to create this cron job?

Shell Programming and Scripting
1

Hello All,

Hope this finds you well. I am creating this shell script that will create cron jobs in crontab file. What I am provided with is the start time , intervals and # of trials. Based of Start time ( say 7:15 am ) and interval being 15 minutes, # of trial being 5 , I should create cron job with following time ...

07:15 07:30 07:45 08:00 08:15

now I would create cron job for this time requirement as ...

15,30,45,00 07,08 * * * command.....

But above would also run command at 07:00 , 08:30, 08:45 ....which is not required. I am using Bourne Shell (sh) . Would appreciate your help in this regards. Let me know if I missed on some.

Thanks,
Sam

2

create the cron job with two lines :

15,30,45 07 * * * command.....
00,15 08 * * * command.....

3

Hello ThobiasVakayil,

So besides spliting them into 2 lines, there is not other solution ....is this correct ?

Thanks,
Sam

4

I think it is the solution.
B'cos there is no match between the minutes entry.

5

Its not possible in any way.
In single line we cant give the timings.
need to put in different lines for each execution on the same field(*).

6

If you insist on having one line only in cron you could create an intermediary script which starts your job at the correct times using the "at"-command. This script could be invoked by cron. Crontab would look like this:

15 7 * * * * my_startscript.sh

and my_startscript.sh would look like this:

#!/bin/sh

echo "/my/app -options" | at now
echo "/my/app -options" | at now + 15 minutes
echo "/my/app -options" | at now + 30 minutes
echo "/my/app -options" | at now + 45 minutes

exit 0

I hope this helps.

bakunin