Shell Programming and Scripting

1. There is no such thing as if you have crontab scheduled after long time.

Above is your misunderstanding.

2. Something else is the mistake....
Definitely environment, or your script permissions or some thing else ... when you check at 18:21 and scheduling it later .. i hope you are doing something .. which makes the script to execute.

The above is assumption only.

3. Check your /var/log/syslog to identify this problem. ( in debian )
Check the same in your OS.

m using CentOS and it is not having that syslog fiel, where else can i get that file ??

---------- Post updated at 03:33 PM ---------- Previous update was at 03:14 PM ----------

I hav checked the log

it was in var/log/cron
it shows that it is taking the script, then why the hell is it not working
i just changed the time to next 2 mins to execute, and it executed perfectly, now its time to execute is at 18:20 and m sure, it will not execute, n i really dont know why...

Ok nice, you;ve located the log in the Cent OS.

But what about the error or execution log ?! Meaning, what did you found useful from there ? At both times -- during non-execution & execution ..

Oct 24 14:01:01 gofenetre crond[11563]: (root) CMD (run-parts /etc/cron.hourly)
Oct 24 14:01:01 gofenetre crond[11564]: (root) CMD (/bin/backup36N)
Oct 24 15:01:01 gofenetre crond[11899]: (root) CMD (run-parts /etc/cron.hourly)
Oct 24 15:28:11 gofenetre crontab[12377]: (root) BEGIN EDIT (root)
Oct 24 15:29:45 gofenetre crontab[12377]: (root) REPLACE (root)
Oct 24 15:29:45 gofenetre crontab[12377]: (root) END EDIT (root)
Oct 24 15:30:01 gofenetre crond[8819]: (root) RELOAD (cron/root)
Oct 24 15:30:01 gofenetre crond[12408]: (root) CMD (/bin/backup36N)


this is last entry for the cron job set
it shows that the job is taking the script at 14:01 hrs
Later i made this modification to my cron job

30 09 * * 6 /bin/backup36M
30 15 * * 6 /bin/backup36N
20 18 * * 6 /bin/backup36E

and the job executed well at 15:30 hrs, giving me the backup of sepcified time, if there wud b any issue of environment variable or anything else, then it shud not hav been executed...

What we need to see is what happened around the time that the jobs should have executed and didn't. I suggests that you set up a crontab. When it fails, post the part of the log that covers 1 hour before the failure time to the end of the file.

Oct 24 18:01:01 gofenetre crond[15482]: (root) CMD (run-parts /etc/cron.hourly)
Oct 24 18:20:01 gofenetre crond[15865]: (root) CMD (/bin/backup36E)


thats the last entry to cron log, and again, the script didnt work...

Did you set up the crontab with the variables MAILTO, HOME, and SHELL? Where there any mail messages?

Cron is executing the scripts. But there may be a problem related to the expectations of your scripts.