Error log and cron job

[Vivek_3]

hi,

i have cron job that runs every minute.

* * * * * /script/m2o.sh >> /log/m2o.log 2>/log/m2o_err.log

it generates a empty error log every min.. but i want to generate log only if there is any error.

To be more specific. /script/m2o.sh is a very simple script. It can't produce any error but based on a specific condition it does call another script (probably twice a day) which may produce some errors. i want to log those errors.

please help me to resolve this problem.

Thanks

Vivek

[Craig Rants]

When you call script 2 from script 1 put your error log entry there.

i.e.

script1...
/usr/local/bin/script2 >> /log/script2.out 2>/log/script2_error.out

I think this is what you want.

GL,
C

[Vivek_3]

HI Craig,

Even if i applied your chnages, it is still creating a empty error log in case if there were no errors.

i want to create log if and only if there were some errors.

Hope you can help.

thanks

[Steve Labar]

In your script that creates a log try adding an if statement around the log create to verify there was an error.
ex.
if ( $? -ne 0 ) ; then
cat {your text here} >> error.log
fi

[Vivek_3]

Hi steve,

so you want to say that i have to generate error myself in script through code and then redirect them to a file. i can't catch the errors generated by script it self.

Waiting for reply.

Thanks

[Paula J Frazer-Campbell]

Hi

When redirecting output to a log watch the redirect that you use:-

> will create a fresh log file each time
>> will append to a log file.

Your problem could be that you are creating a fresh log file each time.

So for the 2nd script the redirect of >> should be used so that on the next run the error data is not overwritten.

Paula

[Vivek_3]

hi Paula,

I need to create a fresh error log evry time script runs but i need to create error log if and only if there were some errors.

Any Help ?

thanks

[Steve Labar]

You don't necessarily need to create an error condition, but you need to test if the error condition you want exists. If you described the error condition it might be easier to recommend a test. Some ideas may be
( -f /path/errorlog ) -if error log file exists

( $?ERRORVARIABLE ) -if error variable exists

Another way might be to simply redirect your errout during the command inside the script.
{command} 2> errorlog
This will only send messages to the log in an error state.

Good Luck.
Steve

[Mark Vollmers]

Vivek-

You could also take and either have a second script or append to the first one a check, after the log is created, where if the logfile is empty, then delete, and if it has an entry, append to your permanent log. Something like:

if [ test -s "logfile" ]
then
rm logfile
else
cat logfile >> permlogfile

this way it will always so the checking and delete the empty file.

Mark