Re: efficient way to read a file in reverse

> I also have to use what is installed on these machines (of which there are thousands of them I need to run it on), so that rules out using File::ReadBackwards

It's pure Perl, you could even copy the rather short code into a module of yours.

If you wanna implement it yourself I'd try reading sliding windows² of 4^n kb chunks from the end with seek

reverse those windows
read line by line form the string (you can also open from a string)
reverse the single lines again
If one window is depleted, read the next one and append it to the last window.

I'd put all the logic into a sub which returns those lines or maybe I'd try to create a new IO class.

I remember a similar question not too long ago, you should try super search °

update

°) like Reading the contents of a file from the bottom up

²) sliding windows explained

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

Comment on Re: efficient way to read a file in reverse

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Re^2: efficient way to read a file in reverse by hippo (Archbishop) on Jan 06, 2021 at 14:06 UTC
you could even copy the rather short code into a module of yours. Or better still, use App::FatPacker to create your stand-alone, distributable script. It will do all the hard/dull work so you don't have to. 🦛	[reply]
Re^2: efficient way to read a file in reverse by cmcl (Novice) on Jan 06, 2021 at 17:16 UTC
Thanks for the suggestions Rolf. I think adapting the code from the module sounds like the best bet, though taking a look at the module, I will need to do my homework on what a lot of it means (I only dabble with scripting really), so a good learning exercise! Cheers, Cam	[reply]
Re^3: efficient way to read a file in reverse by LanX (Saint) on Jan 06, 2021 at 17:25 UTC
Hmm it's offering a "tie filehandle" interface, that's not common and rather deep for a beginner (though a good idea) Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply]