linux 下用定时器 备份Oracle 不能成功的问题

filename=`date +%Y%m%d`
/home/app/oracle/product/11.2.0/db_1/bin/expdp system/psss DUMPFILE=schemas_$filename.dmp DIRECTORY=DATA_PUMP_DIR SCHEMAS=,,,  parallel=2 version=11.2.0.1.0/home/app/oracle/prod