Hi All,

I am into this trouble. I have a simple script, say:
/root# cat test1.sh
x= `tail -100 abc.sh| cut -d '|' 2`
echo x = $x >> testlog1
/root#

When I manually run this script, it gives correct output with value of x in testlog1.

/root# cat testlog1
x = 1234
/root#

But when I run this by making entry in crontab, it doesn't give the value :

/root# cat testlog1
x =
/root#

All settings are correct according to me but then why this anamoly, I cannot understand. Somebody please help.

Thanks in advance.
Sumit Dev Bharadwaj

I like shells and scripting, but I am unsure I can give you an exact answer. A guess is you have to output from your script in a different way. Actually I made a timekeeping/alarm script that I had problems with output. I solved it by redirecting its output in the crontab differently. Look up the 'system file numbers' that you direct script output to. I suppose you want to direct it to 'standard output' or 'standard error.' If you do that the rest of your output may just show up. I have forgotten the way to redirect some output, but you use some punctuation such as '>' or '&' and then the number (representing system files such as 'standard error') is probably at the end.

Another thing I suspect is maybe cron does not work well with some of the syntax in your script. That is unlikely though. I think it is a combination of the shell and cron (since programs in your script are maybe running in the background) that has a problem doing all the output. If I did not at least indicate a few things to try, hopefully someone with much more scripting and cron experience can enlighten us.

Try to give the whole path to the commands and files
ie

Greetings!!!

Hey repo, your suggestion was great and even I thought it should work, but when I tried, it didn't wok too :-( .
dchmelik is correct I think. Crontab is not able to recognise some of the commands in any script.
But then I have some other scripts scheduled in crontab, which contain such commands and work well.
I'll be running in a big problem if this doesn't get solved.
Can anybody please help me? Thank you.


Sumit Dev Bharadwaj

the script as written in your post above does not work, because of a syntax error. If you want to extract the second field using cut, you have to put the -f option:
The script has correctly redirected the standard output to teslog1, but the standard error coming from the first line of code should have been sent to the mail of the crontab's owner. Check it using the mail command and you will find the error message.

Pardon me guys, that was my typo here. In actual script it is with -f option, as it gives correct outpout when run manually.
My problem is with crontab. There is some anomaly I am not getting to. Please post your answers as well.

what are he error message cron gives you ?

Have you checked the mail as suggested above? Any mail with standard error from the cron job?

With cron you have to ensure that you use the complete path for all cmds/files. This includes full path to abc.sh....
Also, ensure there is no space either side of the '=' in the assignment
x=`tail -100 abc.sh| cut -d '|' -f2`
Your version appears to have one after the '='.