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Re: Logging problem

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Lew <noone@lewscanon.com> wrote in news:jjftj9$b8q$1@news.albasani.net:

> Novice wrote:
>> Lew wrote:
>>> Novice wrote:
>>>> Arved Sandstrom wrote:
>>>>> Novice wrote:
>>>>> [ SNIP ]
>>>>>>
>>>>>> It would be very helpful if someone could explain what would
>>>>>> happen in a real-world production situation where a long-running
>>>>>> batch program or a constantly-running online program started
>>>>>> writing error messages to the log. What will operators do to be
>>>>>> able to read the log? I'm guessing they force it to close early
>>>>>> and then start a new file or they have a tool that will read the
>>>>>> log file correctly even without the final</log>  tag.
>>>
>>> As mentioned, "tail" or "tail -f".
>>>
>>> Or vi or emacs.
>>>
>>> Or "less".
>>>
>>> Or just about anything.
>>>
>> Okay. As I said, my Unix/Linux is pretty rusty.
> 
> Wha...?
> 
> These programs run on Windows, too.
> 
> This is about OSes. Windows is like Linux in this regard.
> 
>>> Have you looked at any real system's logs?
>>>
>> No.
>>> You should.
>>>
>> I agree. Can you point me to any? I don't have any.
> 
> Go to your nearest real system and ask to see the logs.
> 
> A lot of Apache projects use log4j. Run one of those.
> 
>>>>> As for how do ops support folks read ongoing stuff? Well, surely
>>>>> you must have used 'tail',
>>>>
>>>> I haven't worked on Unix/Linux in a while but I have used 'tail'
>>>> ;-) Frankly, I don't recall if it works on open files but from
>>>> you've said,
>>>
>>>> apparently it does.
>>>
>>> "man tail"
>>>
>>> GIYF.
>>>
>>
>>> If it didn't work on open files, "tail -f" would be pretty useless,
>>> now wouldn't it?
>>>
>> I'm on a Windows system, not a *nix system, and I simply don't
>> remember the details of 'tail'. Yes, I could have and would have
>> looked it up if I really needed to know. I was just making a passing
>> comment that I didn't remember if 'tail' could read an open file.
> "
> Windows is no different in this regard. This is about reading files as
> they're written, not Linux. You need to know the basics of OSes.
> 
> Windows the same thing happens. Substitute "Notepad" for "vi", why
> don't you? 
> 
I've had Notepad refuse to open files because they were in use. (Or was 
that Wordpad? I may be muddling the two....) Therefore, it was not 
intuitively obvious to me that Notepad would always read a file that was 
in use. 

> And "tail" runs on Windows, too. Many programs are available for both
> Windows and Linux. It's the operating system that determines the
> behavior, not whether it's "tail" or some other program.
> 
> So stop throwing those red herrings at us, please. Take the coaching
> and don't make the excuses.
> 
Coaching or bludgeoing? Sometimes it seems like you seize on even 
slightest misstep to emphasize how I am utterly wrong about something.  
This is one such case. 

The topic at hand was how an operator would access a log file that was 
still open. Someone suggested 'tail' as a tool for reading such a file. I 
mentioned in passing that I didn't know it could read an open file. I 
didn't demand that someone tell me whether it could. If I had, you could 
rightly say that I should look it up. I didn't feel any particular need 
then - nor do I now - to go out and determine all the programs on all the 
popular operating systems, including Windows, that can read an open file. 
I didn't know that tail, vi, or emacs were available in Windows versions. 
I'm not actually surprised but I didn't know it. Notepad may or may not 
be able to read an open file - I'm sure I had trouble reading at least 
one open file with either Notepad or Wordpad yesterday but I don't recall 
which - but it's not a big concern to me at this moment. I'm much more 
interested in the big picture so that I can improve my use of logs. When 
I need to read an open file in Windows, I'll figure out how to do that.  

>>>>> or perhaps opened up a decent programming text
>>>>> editor on a file that's being currently written to, or even just
>>>>> looked at console output. Apart from some buffering going on
>>>>> (none, 
>>>
>>> That "console output" one should already be way familiar to you.
>>>
>> Absolutely, I've seen that. But elsewhere in one of the threads I
>> started, I think there was a general concensus that we couldn't
>> necessarily count on consoles being accessible to everyone who would
>> ideally want access to one so I've been trying to think through
>> things without taking for granted that there was was a console
>> available. So I asked myself what someone without a console might
>> experience.... 
> 
> You're mixing topics. I pointed out the console scenario in the
> context of being able to read a file while it's being written. In no
> wise does that carry over to an inference that I'm recommending its
> use for logging. 
> 
I was only trying to find out how operators would read an open file in 
the absence of consoles. I didn't want to blithely assume that a console 
was always going to be at hand. That's all I was trying to say.

> The point you ducked is that this is basic, fundamental, elementary,
> beginner OS knowledge that applies to Windows, too. It's stuff you
> should already know. You must understand the basics of the OS.
> 
> If you did, you'd've known that the ability of "tail" to read files as
> they're written is neither a feature of "tail" nor unique to Linux.
> 
You're obviously better at remembering large numbers of things for a long 
time than I am. I tend not to remember a lot of details due to my less 
reliable memory. Therefore, I don't have a list in my head of exactly 
which programs on each of the major OSes will read open files. I just 
assume that such tools exist and that I might have some of them on my 
computer. If I need to read an open file, I use the tools I have. If they 
don't work, I look for others or maybe even build one of my own. 

I don't memorize the fact that there are Windows version of vi, emacs, 
tail, less, and so forth nor which of them can read a file that is open 
nor whether Notepad or Wordpad or the various other Windows editors can 
handle them. I've never found that I remember things like that 
particularly well. I wish I could. I muddle along as best I can within my 
limitations.

-- 
Novice

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Logging problem Novice <novice@example..com> - 2012-03-08 19:38 +0000
  Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 14:48 -0500
    Re: Logging problem Novice <novice@example..com> - 2012-03-08 20:06 +0000
      Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 15:38 -0500
        Re: Logging problem Martin Gregorie <martin@address-in-sig.invalid> - 2012-03-08 22:02 +0000
      Re: Logging problem Patricia Shanahan <pats@acm.org> - 2012-03-08 14:53 -0800
        Re: Logging problem markspace <-@.> - 2012-03-08 15:20 -0800
          Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 19:48 -0500
            Re: Logging problem Patricia Shanahan <pats@acm.org> - 2012-03-08 17:17 -0800
              Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 20:55 -0500
                Re: Logging problem markspace <-@.> - 2012-03-08 18:01 -0800
                Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 21:19 -0500
      Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 20:56 -0500
  Re: Logging problem markspace <-@.> - 2012-03-08 14:18 -0800
    Re: Logging problem Novice <novice@example..com> - 2012-03-09 01:53 +0000
      Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-08 20:59 -0500
      Re: Logging problem Novice <novice@example..com> - 2012-03-09 05:36 +0000
        Re: Logging problem Patricia Shanahan <pats@acm.org> - 2012-03-09 06:27 -0800
        Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-09 12:31 -0500
          Re: Logging problem Novice <novice@example..com> - 2012-03-09 18:57 +0000
            Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-09 14:26 -0500
        Re: Logging problem Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-09 15:59 -0400
          Re: Logging problem Novice <novice@example..com> - 2012-03-09 21:32 +0000
            Re: Logging problem Lew <lewbloch@gmail.com> - 2012-03-09 13:56 -0800
              Re: Logging problem Novice <novice@example..com> - 2012-03-09 22:57 +0000
                Re: Logging problem Martin Gregorie <martin@address-in-sig.invalid> - 2012-03-10 14:51 +0000
                Re: Logging problem Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-10 13:00 -0400
                Re: Logging problem Lew <noone@lewscanon.com> - 2012-03-10 10:04 -0800
                Re: Logging problem Martin Gregorie <martin@address-in-sig.invalid> - 2012-03-10 20:23 +0000
                Re: Logging problem Lew <noone@lewscanon.com> - 2012-03-10 07:56 -0800
                Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-10 12:05 -0500
                Re: Logging problem Lew <noone@lewscanon.com> - 2012-03-10 10:10 -0800
                Re: Logging problem Arne Vajhøj <arne@vajhoej.dk> - 2012-03-12 16:13 -0400
                Re: Logging problem Novice <novice@example..com> - 2012-03-10 20:10 +0000
            Re: Logging problem Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-03-09 19:15 -0400
              Re: Logging problem Novice <novice@example..com> - 2012-03-10 01:59 +0000

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