Rewriting the GNU Coreutils in Rust [LWN.net]

Rewriting the GNU Coreutils in Rust

Posted Jun 9, 2021 21:23 UTC (Wed) by wahern (subscriber, #37304)
In reply to: Rewriting the GNU Coreutils in Rust by Sesse
Parent article: Rewriting the GNU Coreutils in Rust

> I'm not 100% sold on its grouping output, and sometimes, it skips files it shouldn't, but doing “rg foo” and having it do -r by default, skip .o files etc. is actually better than the behavior I came to get used to over 20 years with GNU grep.

That sounds very nice from the standpoint of interactive use. But for non-interactive scripting such behaviors violate numerous best practices, and are neither particularly convenient, consistent, nor safe. This is a common story for tools like ripgrep.

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Rewriting the GNU Coreutils in Rust

Posted Jun 9, 2021 21:28 UTC (Wed) by rahulsundaram (subscriber, #21946) [Link] (2 responses)

> But for non-interactive scripting such behaviors violate numerous best practices, and are neither particularly convenient, consistent, nor safe. This is a common story for tools like ripgrep.

Why is this a problem? It is a easy toggle to turn on/off

Rewriting the GNU Coreutils in Rust

Posted Jun 11, 2021 23:12 UTC (Fri) by jccleaver (guest, #127418) [Link] (1 responses)

> Why is this a problem? It is a easy toggle to turn on/off

Because a system administrator may spend lots of time iterating between executing command lines, writing those command lines into a shell script, and debugging said command lines.

Predictability is vitally important, especially if it's 3am and I'm trying to figure out why this shell script that had been working suddenly breaks in the script but works fine when executed by hand.

There's a reason code deltas for interactive operation were few and far between, and mostly invisible (eg, stripping color). When the utility didn't handle it, "standard" shell aliases (eg, "rm -i") could do the trick. Plenty of utilities in the last decade seem to think that I *always* want a huge, complex TUI for getting data, or think it knows better about how I want my output presented.

I have high confidence that grep in an interactive shell and grep in a shell script will do essentially the same thing (except for things that apply to all scripting, like proper handling of globs). I have little confidence a "modern" grep replacement won't have some weird hacky behavior that was put in because it looks cool and will cost me an hour of hair-pulling early in the am trying to track it down.

Rewriting the GNU Coreutils in Rust

Posted Jun 12, 2021 3:17 UTC (Sat) by rahulsundaram (subscriber, #21946) [Link]

> Because a system administrator may spend lots of time iterating between executing command lines, writing those command lines into a shell script, and debugging said command lines.

I suspect from your response that you haven't used rg.

I have written plenty of scripts using both grep and occasionally rg as part of my work and I consider either behavior very much predictable and documented. If anything grep behavior is slightly less predictable when switching between say a laptop running Mac and a server running Linux because of the variations between grep.