if you encounter this error while starting oracle

/etc/init.d/oraemctl start Starting Oracle EM DB Console:
Environment variable ORACLE_UNQNAME not defined. 
Please set ORACLE_UNQNAME to database unique name. OK

# vi /etc/init.d/oraemctl

and add the following code in blue

#!/bin/bash
#
# oraemctl Starting and stopping Oracle Enterprise Manager Database Control.
# Script is valid for 10g and 11g versions.
#
# chkconfig: 35 80 30
# description: Enterprise Manager DB Control startup script

# Source function library.

. /etc/rc.d/init.d/functions

ORACLE_OWNER="oracle"
#ORACLE_HOME="/opt/oracle/otk/home"
ORACLE_HOME="/opt/oracle/otk/home/app/oracle/product/11.2.0/dbhome_1"
ORACLE_SID=orcl

case "$1" in
 start)
  echo -n $"Starting Oracle EM DB Console:"
  su - $ORACLE_OWNER -c "ORACLE_SID=$ORACLE_SID $ORACLE_HOME/bin/emctl start dbconsole"
  echo "OK"
  ;;
 stop)
  echo -n $"Stopping Oracle EM DB Console:"
  su - $ORACLE_OWNER -c "ORACLE_SID=$ORACLE_SID $ORACLE_HOME/bin/emctl stop dbconsole"
  echo "OK"
  ;;
 *)
 echo $"Usage: $0 {start|stop}"
;;
esac
~