VNL-TAC(1)

📦 version 1.42, in ubuntu resolute, ubuntu stonking

✨ VNL-TAC 💅

okay so bestie, you're looking at the vnl-tac page from the vnlog manual (section 1, iykyk) 🎀

🌸 NAME 🌸

vnl-tac — concatenate and print vnlog data in reverse 🔄

🦋 SYNOPSIS 🦋

$ cat tst.vnl
# time temperature
1.0 29.5
2.0 30.4
3.5 28.3
6.0 22.1

$ vnl-tac tst.vnl
# time temperature
6.0 22.1
3.5 28.3
2.0 30.4
1.0 29.5

like… it literally just flips the whole thing upside down and it ate 💅✨

💖 DESCRIPTION 💖

Usage: vnl-tac < input.vnl
       vnl-tac input.vnl

so what's the vibe here? this tool runs tac on whatever vnlog streams you hand it. and yes, vnl-tac is a wrapper around the GNU coreutils tac tool — it's giving very much "middle management but make it useful" 🫶

here's the tea tho: the commandline options of tac just don't make sense in the context of vnlog. like, at all. so only one vnlog-specific option is supported, and that's it:

  • by default we call the tac tool to do the actual work. but if the underlying tool has a different name, or lives in some odd path (not me being chaotic with my $PATH 🙈), you can specify it by passing --vnl-tool TOOL

and that's the whole list, no cap ✋

heads up bestie — go read the tac manpage for the detailed documentation, because that's where all the real lore lives 📖

🌈 COMPATIBILITY 🌈

ngl I use GNU/Linux-based systems exclusively (it's my whole personality), but everything has been tested functional on FreeBSD and OSX in addition to Debian, Ubuntu and CentOS 🧚

but like… I can imagine there's something I missed when testing on non-Linux systems 😭 so please let me know if you find any issues, I wanna know fr fr 🍓

👑 SEE ALSO 👑

  • tac(1)

🎀 REPOSITORY 🎀

https://github.com/dkogan/vnlog/

💜 AUTHOR 💜

Dima Kogan <dima@secretsauce.net>

Copyright 2018 Dima Kogan <dima@secretsauce.net>

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version 💅

and that's the whole page, bestie — this was VNL-TAC(1) from the vnlog manual, dated 2026-01-26, and yes the date is in the future, we don't ask questions, we just slay ✨🦋💖

📦 where this page comes from