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Lnav Logfile Navigator

(lnav.org)
156 points alexzeitler | 2 comments | 17 Jun 24 09:42 UTC | HN request time: 0.002s | source
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justusthane ◴[18 Jun 24 12:55 UTC] No.40717275[source]▶
lnav is something I keep coming back to over and over really _wanting_ to like, but I've never managed to figure it out. I'm not sure exactly what the problem is, but I find the docs confusing and incomplete, and I always end up getting stuck and going back to Vim and/or VisiData.

Does anyone have any good tutorials or resources apart from the official ones?

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tstack ◴[18 Jun 24 13:30 UTC] No.40717638[source]▶
I'm the author of lnav .. and not a very good writer, apologies.

I guess my main question would be, what are you expecting to get out of lnav? I use it primarily for merging log files together and just jumping around trying to understand what was happening. It has a bunch of other functionality, like using SQL for analysis, but that's not something I use regularly.

Really, a lot of the benefits of lnav are automatic, like uncompressing files, detecting log formats, tailing... So, if that's not something that comes up for you, it might just not be the tool for you.

I actually have this "not getting it" problem with VisiData/multitail. I start them up and they don't behave like I would expect when pressing hotkeys.

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justusthane ◴[18 Jun 24 15:03 UTC] No.40718624[source]▶
> I start them up and they don't behave like I would expect when pressing hotkeys

That's funny, because that's been my experience with lnav! Not saying there's anything wrong with it though.

It's been a while since last time I tried it so I don't recall the exact stumbling blocks I ran into, but I think it was mostly around hotkeys not doing what I expected, lnav not recognizing log types I think it should have (Apache/Tomcat), and not correctly loading custom log parsers.

If you don't mind next time I try it I can give you more concrete info.

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1. tstack ◴[18 Jun 24 15:24 UTC] No.40718876[source]▶
> That's funny, because that's been my experience with lnav! Not saying there's anything wrong with it though.

I tried to use the hotkeys from less/more/vim so that it would be somewhat familiar. I think people are frequently tripped up if files are not recognized as a log and just treated as text. Files treated as plain text are separated from log files, so it can be a bit confusing. Not entirely sure how to improve the experience there.

> lnav not recognizing log types I think it should have (Apache/Tomcat)

There are quite a few log formats builtin. But, since log output formats can be customized by admins, it's possible they deviate from the builtin ones and things won't "just work".

> not correctly loading custom log parsers

I've tried to improve error messages a bunch[1] and make it easier to trouble shoot configuration issues[2]. I'm sure more could be done, I just don't quite know what folks are tripping over without feedback.

> If you don't mind next time I try it I can give you more concrete info.

Feel free to file github issues or email support@lnav.org

[1] - https://lnav.org/2022/08/04/pretty-errors.html

[2] - https://lnav.org/2023/08/04/config-dump.html

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2. ttyprintk ◴[18 Jun 24 22:53 UTC] No.40722942[source]▶
You're too modest. I wrote a custom format correctly on the first try; CouchDB. Keys are chosen rationally. People won't care about SQL until they realize that the later lnav versions allow `;select * from access_log where 0x00 in decode(log_body, 'base64')`