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RE: Cron Problem



I wrote:
>> Have you redirected stdout to stdin ...

Graham Smith wrote:
> ... (I think you mean stderr to stdout).

Yes.  My mind jelly turning into seems to be lately...  :-)


> Although I've been using Linux for a while I haven't learnt much
> about the shell.

Get this book:

    http://www.oreilly.com/catalog/bash3/index.html


> ... abandons it's output and relies on cron to mail it to me.

I find it's easier/ faster to debug if I dump everything into a log file.  YMMV.


> just the amount of time it takes to run.

I had similar questions, and that's why I put the `date` invocation into the
scripts run by cron:

    echo    ===== `date` ===== end: '$Id: cron-backup,v 1.9 2004/12/08 0
5:59:11 dpchrist Exp $' =====                       2>&1 | tee -a $LOG


Without the Bash book and knowledge of CVS, the above line may look like
gibberish.  I'll try to translate:

    echo   the echo(1) command -- print command-line arguments on
           stdout

    =====  something that's easy to see in a crowded log file.

    `date` invoke the date(1) command and substitute the output in this place

    end:   a string that matches a similar "begin:" line earlier in the script

    '$Id: cron-backup ...$'
           I keep this script under version control using cvs(1).  $Id$
           is a CVS keyword that is expanded by cvs whenever I check out
           the file.  It is enclosed in single quotes so that the bash
           shell doesn't try to execute any of the stuff in there.

     2>&1  redirect stderr to stdout

     |     send the stdout of the previous command to the stdin of the
           next (shell command pipe)

     tee   the tee(1) command -- copies stdin to stdout and stdin to a
           file

     -a    append option for tee(1) command

     $LOG  expanded by the Bash shell to be the value of the shell
           variable LOG; e.g. the name of the log file


BTW here is the book for CVS:

    http://cvsbook.red-bean.com/


HTH,

David



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