Shell Programming and Scripting

I have an event log which is a circular file. I would like to be able to see real-time updates of that event log. Kind of the equivalent of a 'tail -f'. But obviously 'tail -f' won't work if my circular file has already cycled over. Any ideas as to how I can do this? Let me know if I am clear. Thanks.

Are there timestamps in the file?

Please post an excerpt containing a section where the wrap over happens.

The events in the circular file have a time stamp. A typical circular file with a wrap over looks like this:

03/11/09 15:00:00 blablabla <=== beginning of circular file
03/11/09 15:01:00 yadayada
03/11/09 15:03:00 whatever! <=== latest update to circular file
03/11/09 14:55:00 hahahaha <=== will be overwritten next
03/11/09 14:57:00 i c ded p'pl
03/11/09 14:59:00 l8terz <=== end of circular file (wrap over)

In this particular example, the circular file can only hold 6 lines. The file wraps over when it reaches the end.

I want to be able to look at the updates in a realtime/sequential order. So if I were to do that now, I get the following echo to the screen:

$my_function

03/11/09 15:04:00 shlkfhdsfds
03/11/09 15:05:00 hahahakdfjdjfd
03/11/09 15:07:00 usuejfpsdff
03/11/09 15:08:00 pdspdsfpdf
(this would keep reporting until I stop it)

Even thought the circular file would look like this:

03/11/09 15:08:00 pdspdsfpdf
03/11/09 15:01:00 yadayada
03/11/09 15:03:00 whatever!
03/11/09 15:04:00 shlkfhdsfds
03/11/09 15:05:00 hahahakdfjdjfd
03/11/09 15:07:00 usuejfpsdff

Hope this helps!

Does this help?

Code:

 $ cat temp.txt | sort | tail
03/11/09 14:55:00 hahahaha <=== will be overwritten next
03/11/09 14:57:00 i c ded p'pl
03/11/09 14:59:00 l8terz <=== end of circular file (wrap over)
03/11/09 15:00:00 blablabla <=== beginning of circular file
03/11/09 15:01:00 yadayada
03/11/09 15:03:00 whatever! <=== latest update to circular file

You could run this with the 'watch' command if it's available on your system. How big does this file get?

Do this every 10 seconds:

Code:

watch -n 10 'cat temp.txt | sort | tail'

files grow to about 1megabyte. How do I escape this command once I start it? Thanks allot. Will try this.

CTRL + C will kill it, just like anything else. You're welcome. A megabyte isn't too big, so that shouldn't be too much of a burden on the machine.

any way to do this without relying on the time stamp? I ask because some of the events happen so quickly that they share the same time stamp.