Overcoming “ps: write error: Bad file descriptor” Error at WSO2 ESB 4.8.1 startup as background service.

When you try to start up the WSO2 ESB 4.8.1 as a background service in linux, sometimes you will get the below error.

ajanthan@ajanthan-ThinkPad-T440p:~/wso2/queries/wso2esb-4.8.1/bin$ sh wso2server.sh start
ps: write error: Bad file descriptor

Even we get this error, the ESB console will be accessible through management console. To overcome this issue we need to do the below modification at the wso2server.sh file line number 177.

"if ps p $PID >& ; then" TO "if ps -p $PID > /dev/null ; then".