Having problems running shell script from crontab

[Kaya Saman]

On 01/07/2012 03:05 PM, Yuri Pankov wrote:
> On Sat, Jan 07, 2012 at 02:21:51PM +0200, Kaya Saman wrote:
>> Hi,
>>
>> I wrote a shell script to detect if the port of tomcat was in use or not
>> then restart if the port wasn't online; due to tomcat segfaulting as my
>> system hasn't got enough memory for it.
>>
>>
>> This is the shell script:
>>
>>
>> #!/usr/local/bin/bash
>> ntstat=`netstat -ap tcp | grep 8180 | sed -n '1p'`
> sockstat would be more useful here.

So if I adapted to:

ntstat=`sockstat | grep java`
port="java"

(keeping the same variables in order to limit change - even though 
minimal) then compared in my IF statement below that would have the same 
result? I've never used sockstat although just peeked at the manual 
quickly now:

http://www.freebsd.org/cgi/man.cgi?query=sockstat&sektion=1

>
>> port="8180"
>>
>> #echo $ntstat
>> #echo $port
>>
>> if [[ $ntstat =~ $port ]]; then
>>      echo "Output of Netstat command $ntstat port number $port">
>> /root/java_restart/java_restart.log;
>> else
>>      wait 60; /usr/local/etc/rc.d/tomcat6 restart;
> Are you sure you want 'wait' here (or should it be 'sleep')?

It was sleep that I wanted - thanks! :-)

Sorry my shell scripting skills are really iffy at best.....

>
>> fi
>>
>>
>>
>> Here in /var/log/cron - it can be seen that the script has been executed:
>>
>> Jan  7 10:30:00 wiki /usr/sbin/cron[19509]: (root) CMD
>> (/root/java_restart/java_restart.sh)
>> Jan  7 11:00:00 wiki /usr/sbin/cron[20418]: (root) CMD
>> (/root/java_restart/java_restart.sh)
>> Jan  7 11:30:00 wiki /usr/sbin/cron[21356]: (root) CMD
>> (/root/java_restart/java_restart.sh)
>> Jan  7 12:00:00 wiki /usr/sbin/cron[22455]: (root) CMD
>> (/root/java_restart/java_restart.sh)
>>
>>
>>
>>
>> The strange thing is that if I run this script manually
>> /root/java_restart/java_restart.sh it works fine and does what it's
>> supposed to do. Cron however seems to execute the IF statement but not
>> get as far as else??? - it seems as tomcat doesn't restart.
>>
>> Here is my little log file that tells the port is active:
>>
>> -rw-r--r--  1 root  wheel  116 Jan  7 11:30 java_restart.log
>>
>>
>> If I stop tomcat just before the xx:00 or xx:30 time designations tomcat
>> will not be restarted by the script and I don't understand why?
>>
>>
>> This is the crontab: 0,30 * * * * /root/java_restart/java_restart.sh
> Try changing it to /usr/local/bin/bash /root/java_restart/java_restart.sh.

Ok adapted the crontab let's see what happens now.

>
>> which is being run as root user.
>>
>>
>> Can anyone suggest anything that might be a possible cause for tomcat
>> not getting restarted automatically when the proper conditions are met?
>
> Yuri

Thanks Yuri :-)



Regards,

Kaya