Below is a shell script  which backup dmpfile to ASM storage everyday:

#!/bin/bash

#asmcmd mkdir DATA/ASM_DATAPUMP_BACKUP
#create directory ASM_DATAPUMP_BACKUP as '+DATA/ASM_DATAPUMP_BACKUP';
#grant read,write on directory ASM_DATAPUMP_BACKUP to system;
#create directory LOGDIR as '/s01/logdir';
#grant read,write on directory LOGDIR to system;
#create directory DMPBACKUP as '/s01/dmpbackup';
#grant read,write on directory DMPBACKUP to system;

export ORACLE_HOME=/s01/oracle/product/11.2.0/dbhome_1;
export ORA_CRS_HOME=/s01/grid;
export ORACLE_SID=PROD1;
export PATH=$ORACLE_HOME/bin:/s01/grid:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/home/oracle/bin:/home/oracle/bin:$ORACLE_HOME/OPatch;
thisday=`date "+%Y""%m""%d"`;
expfilename='maclean'$thisday'.dmp';
explogname='maclean'$thisday'.log';
yesterday=`date -d "1 days ago" +%Y%m%d`;
yesterdayfile='maclean'$yesterday'.dmp';
expdp system/system schemas=maclean directory=ASM_DATAPUMP_BACKUP dumpfile=$expfilename logfile=LOGDIR:$explogname;

#TRANSFER FILE FROM ASM TO FILESYSTEM

sqlplus / as sysdba <<EOF
exec DBMS_FILE_TRANSFER.COPY_FILE('ASM_DATAPUMP_BACKUP','$expfilename','DMPBACKUP','$expfilename');
EOF

export ORACLE_SID=+ASM1;
export ORACLE_HOME=/s01/grid;
$ORACLE_HOME/bin/asmcmd rm DATA/ASM_DATAPUMP_BACKUP/$yesterdayfile;
#/usr/bin/find /s01/dmpbackup -mtime 1 -name 'maclean*.dmp'  -exec /bin/rm -rf {} \;
#asmcmd cp DATA/ASM_DATAPUMP_BACKUP/$expfilename /s01/dmpbackup;