Delete Oracle records from a bash shell script

ShellDeleteOracleRecords.sh

#!/bin/bash
#Delete Oracle table since 1 natural year
#

ANO=$(date +%Y)
ANTERIOR=$[ANO-1]
FBORRADO=$(date +%d-%m-$ANTERIOR)
 
MES=$(date +%m)
MESANTERIOR=$[MES-1]
 
if [ $MESANTERIOR -lt 1 ]; then
	MESANTERIOR=12
	ANO=$ANTERIOR
fi
FBORRADO2=$(date +%d-$MESANTERIOR-$ANO)
 
SENTENCIA1="delete from historico where HIST_FECHAALTA < to_date('$FBORRADO','dd-mm-yy');"
 
sqlplus -s /nolog << EOF
set echo on
connect user/schema@db

 
$SENTENCIA1

commit;
 
exit sql.sqlcode
EOF
exit