Crontab script

[Kövesdán Gábor]

Hello,

thanks a lot, it is a more advanced idea, I'll consider using it, but 
since then I've realized what caused my problem. I mistyped a line, and 
I should have written 2>&1 instead of 2>$1. I haven't been very advanced 
in shell scripting yet. :)

Cheers,
Gábor

Paul Schmehl wrote:

> ----- Original Message ----- From: "Kövesdán Gábor" 
> <gabor.kovesdan at t-hosting.hu>
> To: <freebsd-questions at freebsd.org>
> Sent: Sunday, February 13, 2005 1:13 PM
> Subject: Crontab script
>
>
>> Hi,
>>
>> I've seen somewhere an easy way to check whether a program with a 
>> specified pid is running or not. I've made a crontab script to check 
>> my programs based on this. The script is the following:
>>
>> #!/bin/sh
>> PID_FILE="/usr/local/bopm/var/bopm.pid"
>> PID=`cat $PID_FILE`
>> EXECUTABLE="/usr/local/bopm/bin/bopm"
>>
> Check for a pid file is not a good way to see if a program is running. 
> *Sometimes* they will be running even though there is no pid file 
> (even though there's supposed to be one.)
>
> This would be bettter:
>
> either ps -auxw | grep {program name} | awk {'print $2'}
> or pgrep {program name}  (pgrep is available on the web)
>
> If you chose the former, you may have to put in a second grep to 
> eliminate "finding" your own command.  Something like this:
> ps -auxw | grep {program name} | grep {commandline switch of the 
> program} | awk {'print $2'}
>
> You will want to test this on the commandline first to make sure 
> you're getting the right process.
>
> Putting this all together then, with a specific example that I know 
> about:
>
> #!/bin/sh
>
> APACHE=/usr/local/sbin/apachectl
> PID=`ps -auxw | grep httpd | grep "\-DSSL" | grep root | awk {'print 
> $2'}`
> DATE=`date +"%m-%d-%H:%M:%S"
> LOG=`tail /var/log/httpd-error.log`
>
> if  [ ! -z $PID ]; then
>  $APACHE start
>  echo "Restarted apache at $DATE"
>  echo $LOG
> fi
>
> This will check to see if it's running, and if it's not, start it and 
> send you the date/time it was started and the last 10 lines of the 
> error log. Since you're running it in cron, you'll get email with the 
> output.  If you wanted, you could redirect stderr to a log to see if 
> there were any problems.
>
> Paul Schmehl (pauls at utdallas.edu)
> Adjunct Information Security Officer
> The University of Texas at Dallas
> AVIEN Founding Member
> http://www.utdallas.edu/~pauls/