hi everybody.
please help me in understanding this code.



echo "************* starting job on `date +\"%d/%m/%Y at %T\"` **************"
#
scriptdir=`dirname $0`
. ${scriptdir}/env_params.sh
#
SHLIB_PATH=${ORACLE_HOME}/lib:
export SHLIB_PATH
export LD_LIBRARY_PATH=${ORACLE_HOME}/lib:/usr/lib
export NLS_LANG=AMERICAN_AMERICA.US7ASCII

BDIR=${hotbackupdir}/`date +%a`
export BDIR

#if instance is not running, abandon

ps -aef | grep pmon_${ORACLE_SID} | grep -v grep > /tmp/check_sid
if [ -s /tmp/check_sid ]
then
echo ' '
echo "**** ${ORACLE_SID} instance is running, hot backup will be run ****"
echo ' '
else
echo "**** ERROR! ${ORACLE_SID} instance is not running, hot backup will not be run ****"
exit 1
fi

cat /tmp/check_sid > /tmp/hb.log