Hacker News Reader

Comment by betawolf33 | Hacker News Reader

In a sense, yes. However, some of the things ls does are 'borrowed functionality'. That the displayed listing can be sorted by a flag to ls is a bit of an aberration in the Unix philosophy. We're meant to have a separate tool for sorting - sort.

I agree that a certain flexibility is useful in the Unix tools, but a well-founded argument can be made that flexibility costs you simplicity.

View on HN

The fact that ls can produce output that can't be reliably sorted using the sort utility shows that ls is actually doing three things instead of just one: Listing files, sorting the output and then displaying the output in a human readable format.

This is not to criticize ls though - I would imagine that no matter how small the operation (well aside of operations executed directly by the cpu), there's still the possibility to break it up into smaller parts.

At some point convenience just trumps modularity.

ls -lt is just more convenient than a (hypotetical) ls -t | sort | xargs fileinfo | display-fileinfo

On a related note: Windows PowerShell comes closer to this ideal by being able to send arbitrary objects between pipes. This still has the side-effect though that single commands become much more awkward to use as they don't produce output that's usable on its own.

    I would imagine that no matter how small the operation
    (well aside of operations executed directly by the cpu),
    there's still the possibility to break it up into smaller
    parts.

The scripting system could have been designed to make layering easier. Bourne descendants are ugly and awkward. Hence, unix evolved into a situation where ls had lots of features, whereas were there a better scripting system, we might have had a standard environment which you could introspect deeper and extend with more confidence.

> The scripting system could have been designed to make layering easier.

How? sh sucks for anything involved, but I can't think of a way to simplify pipelines much.

A line oriented xargs could have been built in from day one.

A pair of shell variables honored by commands that let you specify output wrappers or separators would have been nice too. Think "-Q" in gnu ls, but universally supported and user-controlled.

How would you make 'sort' do all the things that 'ls' can easily do?

How do you sort a multi-column output by 3rd column?. You have to write some scripts for that.

sort -k 3

That works for the trivial case of the 3rd column, but not for everything ls can produce. There's no way to make sort work on dates as formatted by ls (which may or may not have years or hours, depending on how old) or sizes (which you may want to pretty print as human readable.)

What sort option puts 1.0K, 1.0M, and 1.0G in the right order?

While I do appreciate the point that ls is doing sorting that sort would struggle to manage, isn't this an argument for better functionality in sort?

Someone pointed out that ls is really doing three things - listing files, sorting them and displaying them. That seems fairly accurate, and indeed it's convenient that it does.

But it's not 'doing one thing'. I'm not saying that's necessarily bad (as I just said, it's convenient), but it's not hardline Unix-way purity.

For practical reasons like those you raise, it makes sense for ls to handle its own sorting rather than leave it to the sort command, just as it handles its own formatting rather than let the user manage it. But those features _are_ something other than just reporting file listings, whatever the motivation for the feature creep. This convenient flexibility makes ls less single-task, less Unix-adherent but more generally useful on its own.

> There's no way to make sort work on dates as formatted by ls (which may or may not have years or hours, depending on how old) or sizes (which you may want to pretty print as human readable.)

Both of which wouldn't be the job of a "do one thing and do it well" `ls`. That one would display dates as a UNIX timestamp and sizes as bytes. Aside from that, surely if ls can format information it's possible to reverse that formatting.

Sure. Instead of running ls -lhrT, I could run ls -l | sort -n -r -k 5 | prettydate -k 6 | prettysize -k 5. Maybe make a shell alias. But at some point, I don't want my day to day life to be one big puzzle solving mission, I just want to get shit done. Is unix going to ship with 900 prettyX scripts, or do we make everybody write their own awk script?

Here's another thought I had about the old school unix way. Old school unix didn't have symlinks. The purpose of the filesystem is to store files, right? If you want aliases, then you should keep them in a file like /etc/symlinks. Or ~/.symlinks, then every user can have their own aliases. That's the real unix way, right? Let's not take the minimalism to absurd extremes.

Reply on news.ycombinator.com