fix uniq -c [LWN.net]

fix uniq -c

Posted Feb 17, 2025 18:46 UTC (Mon) by stijn (subscriber, #570)
In reply to: fix uniq -c by mbunkus
Parent article: Rewriting essential Linux packages in Rust

I chose a very poor title ('fix unic -c') for what I wrote, implying the presence of a bug. What I meant was

- current default behaviour of uniq -c is poor for composing.
- let's add an option so that we can have the behaviour that I like.

With this, we can have both a 'visually clear' format and a suitable-for-composing format. For compatibility the current format is of course the default in that scenario.

> For example, if you want to process it further via pipes then then awk & bash don't care at all about the right-aligned numbers[1], whereas other programs might.

I work a lot with dataframes, which are essentially mysql tables in tab-separated format with column headers, or equivalently a single table in a spreadsheet, or the things you might want to read with Python pandas or in R. Tab separated is preferred, as I've never encountered a need to escape embedded tab characters. In this wider ecosystem there is no automatic white-space scrubbing of data and a there is a requirement that tables are well-formatted. Programs such comm, join, datamash, shuf and a fair few more can be very handy in summarising, QC'ing or (even) manipulating this data. Hence I clamour for the ability (not necessarily as default) to have all tuple/table type data formatted as tab-separated tables, with or without column names. This should go well with unix composability of processes.

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fix uniq -c

Posted Feb 17, 2025 19:18 UTC (Mon) by mbunkus (subscriber, #87248) [Link] (1 responses)

Alright, I think I understand where you're coming from a lot better now. It wasn't just your title, though; in your first comment you wrote:

> It is quite puzzling that Richard Stallman let this program loose on the world as it violates usual Unix well-behavedness of textual interfaces.

And to that my argument was that first and foremost `uniq -c` was most likely designed to be easy to read by humans. By that metric it is very much well-behaved & doesn't violate anything. Furthermore, even with it being designed to be human-readable its output is actually useable as-is by a lot of other traditional Unix programs, making it arguably even less of a "wrong" that has to be "righted" (your choice of words, again from your first post). Apart from awk & bash which I mentioned earlier, "sort -n" works fine as well.

fix uniq -c

Posted Feb 17, 2025 20:15 UTC (Mon) by stijn (subscriber, #570) [Link]

I let a pointless/misdirected rhetorical flourish get the better of me again. I understand the history - and view it as beneficial to strive towards (recasting it from wrong/right) to make outputs (tuples/tables) preferably by default composable or at least add options to do that without assumptions about white-space padding. The table format (mysql dump, spreadsheet, dataframe) is pervasive and super useful. In the right setup shell pipelines can do amazing things with them. Working in those type of table environments has made the various stripes of unix white-space padding and stripping jar with me.