Delete lines prior to a specific date in a log file.

Shell Programming and Scripting
1

Hi all.

I have a database log file in which log data get appended to it daily. I want to do a automatic maintainence of this log by going through the log and deleting lines belonging to a certain date.

How should i do it? Please help. Thanks.

Example. To delete all lines prior to Jun 3.

My content of my log is like below:
Sun Jun 1 01:38:25 2008
Completed: ALTER DATABASE OPEN
Sun Jun 1 22:00:40 2008
Thread 1 advanced to log sequence 2518
Current log# 1 seq# 2518 mem# 0: /u03/oradata/sbdevdb/redo01.log
Current log# 1 seq# 2518 mem# 1: /u03/oradata/sbdevdb/redo04.log
Mon Jun 2 10:00:33 2008
Thread 1 advanced to log sequence 2519
Current log# 2 seq# 2519 mem# 0: /u04/oradata/sbdevdb/redo02.log
Current log# 2 seq# 2519 mem# 1: /u04/oradata/sbdevdb/redo05.log
Mon Jun 2 22:01:10 2008
Thread 1 advanced to log sequence 2520
Current log# 3 seq# 2520 mem# 0: /u05/oradata/sbdevdb/redo03.log
Current log# 3 seq# 2520 mem# 1: /u05/oradata/sbdevdb/redo06.log
Tue Jun 3 01:30:03 2008
Starting background process EMN0
EMN0 started with pid=20, OS id=639158
Tue Jun 3 01:30:03 2008
Shutting down instance: further logons disabled
Tue Jun 3 01:30:03 2008

2

so basically you want to keep the data after Jun 3 right??
if so you can use

sed -n '/Jun 3/,$p' logfile > newlog

if you have -i option in your sed man page use

sed -n -i '/Jun 3/,$p' logfile
3

Hi. Thanks for the reply.

I tried and it did work to extract all logs after Jan 1. But I want the data from Jan 1 to remain in the original file. The command seems to only be able to pipe the output to another filename instead.

Any other options? Thanks!

4

Hi,

What do you want?
Vidhyadhar reply does exactly what you are looking for.
It is printing only the data which is after june 3 and redirecting it to a new file.

Thanks
NT

5

Hi all.

Vidhyadhar's reply did redirect all logs after Jan 1 to a new file.

But, what i want is log data after Jan 1 to remain in my original file name. My original log filename is alert.log. I want alert.log to hold only data after Jan 1.

Thanks.