Re: [tlug] Apache: Logging: how-to pipe logs or logtoanothermachine (was Disk

[Bruno Raoult <br@example.com>]

On Sun, 2002-09-08 at 15:24, Jean-Christian Imbeault wrote:
> >From: Viktor Pavlenko <vvp@example.com>
> >
> >  From `man gzip`:
> >
> > >if a file name is "-", the standard input is compressed to the
> > >standard output.
> 
> I just tested it out. Gzip will accept input from  STDIN but won't actually 
> create a file until EOF is sent.
> 
> I did "gzip -cd > t.gz", that create a file called t.gz with 0 bytes, let me 
> type input on the console.
> 
> Nothing was written to the file until I hit Ctrl-D ...

I think your test was not correct. gzip uses (with others) lzw
compression which does not need EOF.
The problem is stdio cache, which "caches" data in memory until a BUFSIZ
data is ready (the same problem would occur with *any* pipe, meaning
that with 2 pipes, you could have a 2*BUFSIZ data somewhere...).
Try with a bigger file, like:
	cat /var/log/messages | gzip [etc...]
If your message file is big enough, gzip will write data block by block.
If you want really to see it in action, do:
	(cat /var/log/messages; cat) | gzip [etc...]
This will send to the input of gzip 1) the message file, and 2) your
input.

Bruno.


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