oracle : Scheduling ASH reports through Crontab

I was asked to capture ASH reports every 5 minutes for an ongoing Database issue. Below is the process to schedule it through Crontab

Script to capture the ASH reports every 5 Minutes

$ cat ash.ksh
#!/bin/bash
export TZ=US/Central

dateString=`date +%d-%b-%Y_%H:%M:%S`
sqlplus -s / as sysdba << EOD1
define report_type = 'html'
define begin_time = '-5'
define duration = ''
define report_name = '/u01/user/local/reports/ashrpt.${dateString}.html'
@?/rdbms/admin/ashrpt
exit
EOF

To run it through Cron

0,5,10,15,20,22,25,30,32,35,40,45,50,55 * * * * /u01/user/local/ash/ash.ksh > /u01/user/local/reports/log/ash_collect.log 1>/dev/null 2>&1