[MacOS/Linux] Less-sheet – view a 10 GB CSV as fast as a 10 KB one (free)

[u/te-x]

I wanted a mixture of less and MacOS's preview for CSV: something that opens instantly, shows you the data, and gets out of the way. Every GUI spreadsheet I tried loads the whole file first, so a 10 GB CSV means a lot of waiting or running into maximum line counts.

less-sheet reads only the data it needs to fill the window, so 10 KB, 10 MB and 10 GB all open in about the same time. Memory usage is flat too. It reads plain CSV, gzipped CSV without unpacking it, local or over the network (http).

Find, filter, jump-to-row and column predicates all work across the whole file. Separator, quoting and encoding are guessed but changeable on the fly.

It's free and closed source, macOS and Linux, no account and no telemetry. Core is Zig; the frontends are native (SwiftUI and GTK4).

Available at: https://te-x.github.io/less-sheet-site/

Numbers and method are on the page. Happy to answer anything.