Script help needed

I have a code given below...

ERROR=`grep "Job Status" ${LOG_FILE}`
ERROR=${ERROR##\(}
ERROR=${ERROR%%\)
}
if [ "${failedstart}" = 0 -a "${ERROR}" = 1 -o "${ERROR}" = 2 ]
then
echo "The job completed successfully"
EXIT_STATUS=0
else
echo "The job failed"
EXIT_STATUS=1
fi

can anybody tell me what is
ERROR=${ERROR##\(}
ERROR=${ERROR%%\)
}

is doing...??

i dont understand the command.....## and %% what it does?

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