Shell Programming and Scripting

Hi guys!

Consider the following PERL script,

Code:

#!/usr/bin/perl

my $userID = `whoami`;
open(TMP, ">user.txt");
print TMP "$userID";
close(TMP);

Run on the command line it works no problem.
Run using crontab it doesn't work.
Where do I go to check errors from crontab?
I've read things about the cron ENVIRONMENT which I don't understand.
Could someone please explain to me what I need to know about crontab before I start using it?

crontab line looks like this:

Code:

8 15 * * * /location/of/my/script/cronprob.pl

Thanking you

You would have to write a script that loads the environment first then calls your perl script.
The best to avoid interactive shell issues to put in a separate file you call e.g. profile_perl where you have all needed environment variables set, then you execute it in your batch script for cron as:

Code:

. ~path_to script/profile_perl
/usr/bin/perl ~path_to_script/cronprob.pl

Ok i'm getting that I need to set some environment variables but what variables are these?
What do I need to set them to and how do I set them (yes this thread is appropriately titled!)

Thanks for your response vbe

You set any env variable you need except DISPLAY, TERM TTY and other keyboard stuff since there arent any for cron...
I would imagine PATH is very important and for the rest, look in your .profile or its equivalent what is set that could be used by your script
to set (since cron uses ~/bin/sh):

Code:

PATH=/usr/sbin/:/usr/bin:/usr/ccs/bin:/usr/local/sbin:/usr/local/bin:(etc...)...
export PATH

Supposing all I care about is the /usr/bin directory (assuming that this is the one PERL cares about), can I manually go to this PATH variable and set it = to /usr/bin or are these variables not sitting in a file somewhere like a config file?

/usr/bin is maybe the only thing set in cron with /bin, so if it isnt working then you have more to think about (using libraries? perl can have env settings like java does...)

Is there a way to actually look at these variables and see what they are set to?