I have a log file , that keep the record of system activities , as below , now the log is appending so that it becomes very large .

"
05/01/08 Normal userA
05/01/08 Normal userB
05/02/08 Alnormal userC
"
"
10/01/08 Normal userA
10/02/08 Normal userA
"


Now I would like to keep the log current , so if the date is over 60 days , then remove this row , like above , the first three row should be removed as 05/01/08 and 05/02/08 is over 60 days ( today is 10/08/08 ) , can advise how to do it ? thx