Having problems running shell script from crontab

Kaya Saman kayasaman at gmail.com
Sat Jan 7 12:50:47 UTC 2012


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:

ntstat=`netstat -ap tcp | grep 8180 | sed -n '1p'`

#echo $ntstat
#echo $port

if [[ $ntstat =~ $port ]]; then
    echo "Output of Netstat command $ntstat port number $port" > 
    wait 60; /usr/local/etc/rc.d/tomcat6 restart;

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 
Jan  7 11:00:00 wiki /usr/sbin/cron[20418]: (root) CMD 
Jan  7 11:30:00 wiki /usr/sbin/cron[21356]: (root) CMD 
Jan  7 12:00:00 wiki /usr/sbin/cron[22455]: (root) CMD 

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

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?



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