UNIX for Dummies Questions & Answers

I have a problem with crontab. I made a class file name Mailer.class. When I run it at command line like this:

$ java Mailer

It runs very well and I got the email. But If I put it in a crontab line like this:

30 11 * * * java Mailer

It doesn't work.

Every time the cron job finished, when I type something at command line, I got the "You have mail" sentence.

Please help me. I appreciate any help, comment

Thanks

You have probably lost your CLASSPATH environment variable using cron. Your .profile isn't getting launched in the non-inteactive shell that cron runs. Use -classpath and/or ensure you are setting up your environment using a shell script wrapper.

The mail message you are getting is no doubt related to the failed cron job.

Thank you very much for a quick reply.

I have CLASSPATH environment variable in my .profile. And that is a long string. Do you have any link so I can learn how to set up environment using a shell script wrapper? Or can you give me some note about that?
I'm new to Unix. So please don't laugh at me...

Thanks again

In the simplest form, create a shell script file called Mailer.sh:

Code:

#! /usr/bin/ksh

# Source your .profile parameters
. /home/youruserid/.profile

# or 
export CLASSPATH=yourreallylogclasspath

# add/modify more variables that you need

java Mailer

Make sure your script is executable:

Code:

chmod 755 Mailer.sh

Change your crontab entry to:

Code:

30 11 * * * /someUnixPathToYourScript/Mailer.sh

This thread provides some helpful tips on determining whether or not your shell is interactive.

Hi tmarikle,

Thank you very much for your help. It works very well!!!

I am really appreciate your help.

Quang