From: bradjpeek <bradjpeek@...>
Date: 2009-05-08T03:40:09+09:00
Subject: Re: How can I trim top of file w/o disrupting other writers?

On May 6, 9:15 pm, Julian Leviston <jul...@coretech.net.au> wrote:
> On 07/05/2009, at 9:35 AM, bradjpeek <bradjp...@gmail.com> wrote:
>
> > As a way to learn ruby, I wrote a method to trim the first "n" lines
> > from a log file.   I had planned to use it on a series of log files
> > that are constantly growing.   However, some of the programs that are
> > appending to these logs don't tolerate the somewhat brute-force method
> > I'm using, which is:
>
> > 1) Write the lines I want to keep to a temp file
> > 2) Rename the temp file to the original log file name
>
> > This works fine for some log files, but others stop receiving log data
> > after I run my program.   I suspect it is because they have the file
> > open and don't notice that the inode (or some other pointer to the log
> > file) has been pulled out from underneath them.
>
> Why can't you simply open the file itself for read write then replace  
> the contents? That's worked fine for me before
>

That worked.  Thanks for the embarassingly obvious answer.

Actually, that occurred to me when I first wrote the script and I
can't remember why I chose the rename approach.