Code:
Output when the script runs through cron:
$ cat sar_cpu_040913.csv
20:09:01,CPU,%nice,%iowait,%steal
20:09:11,all,0.00,0.05,0.00
20:09:22,all,0.00,0.03,0.00
20:09:33,all,0.00,0.05,0.03
20:09:44,all,0.00,0.03,0.00
20:09:55,all,0.00,0.03,0.00
20:10:06,all,0.00,0.03,0.00
20:10:17,all,0.00,0.03,0.03
20:10:28,all,0.00,0.03,0.00
20:10:39,all,0.00,0.03,0.00
20:10:50,all,0.00,0.03,0.00
20:11:01,all,0.00,0.25,0.02
20:11:12,all,0.00,0.00,0.00
20:11:23,all,0.00,0.02,0.00
20:11:34,all,0.00,0.03,0.03
20:11:45,all,0.00,0.02,0.00
20:11:56,all,0.00,0.05,0.00
20:12:07,all,0.00,0.05,0.00
20:12:18,all,0.00,0.05,0.03