UNIX for Dummies Questions & Answers

Hi everyone

In an existing crontab script for the root user, I've added 5 new lines of code, however for some unknown reason, these lines of code were not executed.

Here is what I did

Code:

30 0 * * * ./usr/people/atlab/jamesgoh/disk_reader/disk_reporter /picnic
30 0 * * * ./usr/people/atlab/jamesgoh/disk_reader/disk_reporter /paradise
30 0 * * * ./usr/people/atlab/jamesgoh/disk_reader/disk_reporter /chopper
30 0 * * * ./usr/people/atlab/jamesgoh/disk_reader/disk_reporter /bliss
30 0 * * * ./usr/people/atlab/jamesgoh/disk_reader/disk_reporter /nugget

The general idea is that at 12:30 am (that is midnight + 30 mins) each night a C-program called disk_reporter runs to gather disk usage information on the parameter disks (picnic, chopper, bliss, nugget).

If im not mistaken, the syntax of my code above should be correct

Also, when doing an ls -al, I found that the root crontab file (the one Im editing) has read only permsissions for all users and groups in general (it was showing -r--r--r--), however given that I was able to add 5 extra lines of code this is quite bizzare.

However Im still not sure what I've done wrong ? Can anyone help me out here ?

what error message from the cron log or any other error messages ??

Forgive my ignorance, but how do I put error message checking in the command line or crontab script ?

Ok I realised that some causes of the error was not removing the . when specifying the executable (as Im not running it from the directory the executable is in) and using the machine's timestamp (I was using a remote machine's timestamp)

However, the script only worked when we did the adjustements from my boss's machine (he has remote access to the machine the cron script is run from) and not mine.


Im still at lost as to what I could be doing wrong ?

basically to schedule a cron job, just need to ensure the script with path is executable, test to run it manually with right account. Then schedule in crontab and monitor the cron log (eg. /var/log/cron) depend on which unix platform...

See the cron log (usually /usr/adm/cron/log) to see whether the cron ran at all and if it failed with an exit code (rc=n).
Untrapped errors from root cron will be found in root mail.
You can only edit the root cron if you have root permissions.
The cron daemon will only notice the changes to a crontab if they were made with the appropriate "crontab" command or cron itself was restarted.

Hi everyone

I finally managed to get my crontab script to work.

The problem was that I was not doing the editting via crontab -e, which is necessary to update the existing crontab file.