About this part: There are a number of other POSIX-ish shells implemented in a non-C/C++ implementation language
OSH is implemented in an unusual style -- we wrote an "executable spec" in typed Python, and then the spec is translated to C++.
That speeds it up anywhere from 2x-50x, so it's faster than bash on many workloads
e.g. a "fibonacci" is faster than bash, as a test of the interpreter. And it makes 5% fewer syscalls than bash or dash on Python's configure (although somehow this doesn't translate into wall time, which I want to figure out)
It's also memory safe, e.g. if there is no free() in your code, then there is no double-free, etc.
---
As mentioned on the OSH landing page, YSH is also part of the Oils project, and you can upgrade with
Good question -- at first I thought we would use an arena, at least for the parser. But we ended up writing a garbage collector for the subset of C++ we generate!
That was completed in 2023: Pictures of a Working Garbage Collector
(1) The AST (aka "lossless syntax tree") is actually GRAPH - it is useful to share nodes.
I think graphs are fairly common for ASTs. Once a node can have multiple parents, then ownership becomes less clear, and errors using arenas can easily cause memory safety bugs.
For example, in Rust, I think you start using Rc<T> and so forth, which is automatic memory management at runtime.
(2) YSH is part of Oils, and it has nested dicts and lists like Python and JavaScript.
Once you have nested dicts and lists, you need GC. We actually have the GC at the "meta-level", and that (somewhat surprisingly) saves a ton of code and bugs.
It's like writing a Python/Ruby interpreter in Java or Go, and re-using the platform GC, rather than writing one specific to your language.
In particular, we don't have GC rooting, ownership, or anything like Py_INCREF/DECREF littered all over the codebase. This makes our implementation like an executable spec!
And that makes it very easy to contribute -- you write typed Python, and it's as fast as shells written in C. I think it's the best of both worlds
---
Something I've pointed out over the years, and which many people find illuminating, is
- bash doesn't have nested maps and arrays -- it only has flat ones. Therefore it doesn't need GC
I put all these "weak glue" languages in the "string-ish" category. In contrast, YSH gains A LOT of power from having real data structures, and that requires GC.
(Writing a GC was the hardest part of the project -- I think sh/awk/make/cmake left it out for a reason! Even nushell has no GC I believe. fish lacks a GC too.)
YSH has more of the power of Python/JS/Ruby, which if you look at it historically, did "replace" shell and awk for a huge set of problems. (Guido van Rossum specifically mentioned the "hole" between shell and C as a motivation for Python.)
On a different note, if anyone really wants a shell buildable with the Rust toolchain, it would be worthwhile to TRANSLATE Oils to Rust. This will definitely work, because Oils is translated to C++ (completed in early 2024).
You would have to write the runtime, which is around 4K lines for the garbage collector, and 4K lines for the OS bindings. That's a lot easier than writing a bash-compatible shell.
That is, Oils has about 8K lines of hand-written C++ code. Compare with bash which is 162K+ lines of C written from scratch -- it's 20x less.
I think 8K lines of unsafe code is also comparable to Rust binaries. e.g. prior to ~2018, Rust binaries used dlmalloc by default, which is 20-30K lines of C code.
(What's important is that almost all PRs modify safe code only -- it is very easy to review typed Python)
This would be a fun exercise for anybody interested in writing a GC in Rust (which is a hard challenge, with many nontrivial choices). You can write a GC, and get a shell for free, etc.
---
Also, Brush and nushell are different projects ... Oils has both things -- OSH and YSH -- compatible and new
So you actually get 2 shells for free by doing that :-P The "executable spec" strategy took a long time, but it actually worked!
Since everyone is sharing shells written in Rust, I've become quite fond of Nushell: https://www.nushell.sh/
I'd love to see more shell exploring things beyond POSIX. Text based stdin/stdout will always have its place, but having ways to express, serialize, and pass along data in more structured ways is quite nice.
+1 on nushell, it is incredible. Having all data typed and structured is an insane superpower.
Common worries I hear from people that were non-issues in practice:
- Not POSIX compatible: Nushell doesn't aim to replace POSIX, there's no problem with dropping back to bash to execute some shell snippets
- You need to re-learn everything: I'm not a huge fan of how the commands are organized, but I still didn't find it that difficult. nushell's prompt/readline comes with an inline help menu with fuzzy search. Hit CTRL+O to edit a command/pipeline in your IDE/editor of choice with LSP backed intellisense, type-checking and in-editor command docs/help. The syntax is very simple and intuitive.
- Just use python: Sure, but python comes with a lot of disadvantages. It's slow and uses dynamic typing. Static typing in nushell catch typos in pipelines & scripts before they execute. It also makes in-shell and IDE LSP tab-completions very accurate. Large files process quickly though it will still consume more memory if you aren't able to process all the data in a streaming fasion. It's like having jq but with autocomplete and it works on all command output & shell variables. Though if you really like python, check out Oil/OSH/YSH: https://oils.pub/
- All Unix commands output text, structured data is useless in a shell: `detect columns` (https://www.nushell.sh/commands/docs/detect_columns.html) - now it's structured. Or use `from <format>` if the command outputs CSV, JSON, INI, YAML, etc... Or don't, cause GNU tools work fine in nushell if you keep everything in text format
And there are other crazy features too.
- Write nushell plugins in your language of choice, plugins can work with structured data
- Plugins can run in the background and maintain state, nushell can automatically start a plugin when it is first used and stop the plugin when it is idle
- e.g. a plugin can open a SQL connection and use it across multiple commands. There's a built-in plugin for opening in-mem/on-disk SQLite databases
- Data can carry metadata, e.g. binary data can carry its mime type, strings often carry metadata about which line and file the string was read from.
- Ongoing work on DAP suppprt to allow debugging scripts from your IDE
- Create your own hooks to customize how different types of data are displayed. Display structured data in table/tree form, display binary data in hex, etc...
- Collect related commands/variables into modules. Load a module knowing that you can easily unload the whole module later, module contents don't pollute global state. Variable declarations, env vars and loaded modules are scoped to the current code block and disappear after the closing bracket, lowering the odds of a name collision.
- Native support of Polars dataframes to work with even moar data
- Complex parllelism: Message-passing/actor architecture background jobs. Turn-key parallelism: transform every element of a list in parallel - `par-each` (https://www.nushell.sh/commands/docs/par-each.html)
The biggest downside of nushell is that it hasn't hit 1.0 yet so commands occasionally get renamed. Expect that you may occasionally need to tweak a script to get it working again. Definitely a pain point.
Nushell is fun. When I tried it years ago, it was only half-baked.
But a lot of the structured data transformation use cases I encounter, I find myself tackling in DuckDB. It's a little harder for the simplest things, but it pulls ahead quickly. Or at least it does if you need to remember SQL anyway...
I tried really hard to get into Nushell but gave up after a month or two. Muscle memory with backgrounding was my big issue -- I tend to edit in helix and then background for a while and then foreground, and I seem to recall this totally freezing or crashing nushell somehow. Tried to learn some kind of recommended alternate workflow with pqueue (? I think) but just couldn't get there.
Powershell feels like it was designed by people who expect the underlying app to natively structure its data before handing it off to the shell. Typical Microsoft, acting like they own the place and expecting others to conform.
Nushell on the other hand takes the (IMO more pragmatic) stance that the underlying app will most likely be writing strings to stdout and it's the shell's job to make it easy to discern the structure in those strings.
Perhaps a powershell wizard can show me that I'm wrong about this, but my feeling is that the powershell equivalent to this nushell is going to either call some external program (in addition to docker) or be quite messy:
$ docker ps | detect columns | where NAME == "foo"
This might seems like a rant for some of you, of even heretical to certain shell zealots... But it's about time we move past Posix compliance for shells. Don't get me wrong, it was a fabulous thing back in the 1980s and 1990s with respect to the Unix wars. But in a twist of irony Linux won the Unix wars, and these days Posix compliance, with respect to shells, mostly holds back innovation or modernization by pegging the concept of a terminal to something from 1988. Namely the Korn Shell (which is reference POSIX SHELL implementation back then), or even worse the Bourne shell. Doing get me wrong, I'm glad we're not on something like the C shell, but I'm pretty sure nobody today actually adhears to pure Posix compliance for shells scripting. So let's all just agree to drop the pretence snobbery, and move forward in a brave new world beyond Posix.
There are two ways to attempt to move beyond POSIX sh:
1. You can do a superset of POSIX, like BASH and I think Zsh. This gives you a graceful upgrade path while maintaining backward compatibility, at the expense of being somewhat "stuck" in places. Oil is another attempt at exploring how best to use this path.
2. You can throw out POSIX totally, like fish and PowerShell. This lets you really improve things, at the expense of breaking backwards compatibility. IMHO, breaking compatibility is painful enough that it's really really hard to justify.
It's also worth pointing out that you can separate the roles of "interactive shell" and "shell for scripts". It is, for example, perfectly reasonable to use fish for interactive sessions while keeping /bin/sh around and perhaps even preferring dash as its implementation, which gives you compatibility with software while making things friendlier to users. I mean, I say this as someone who writes a lot of sh scripts and between that and years of practice my fingers expect something roughly sh-like, but I hear a lot of good things from folks who just switched their interactive shell to ex. fish.
I'm with you. I've used Fish for a few years now and I find it so much more ergonomic for having foregone strict POSIX compliance. I still write cross-platform stuff in Bash when it's going to run on machines I don't personally control, but I'll write all my routine local interactive stuff (like adding helper functions, wrappers for other commands, etc.) in Fish because it's a breath of fresh air.
I strongly disagree with the notion of only learning one shell language "because what if I telnet into an ancient Sun box and Fish isn't available?" In exactly the same way, I don't exclusively write my programs in C in case some remote host might not have Python or Rust or Fish some day. I'll cross that bridge when I come to it, but in the mean time I want to use something that makes me happy and productive.
Posix compliance isn't holding back progress. You are welcome to make the most advanced, paradigm-smashing new shell in the universe. If it's good, people will use it. If you want it to replace Posix compliant shells, you might want to consider why people might not want to leave Posix and address that first, rather than ask everyone to abandon them "because we're advanced now"
But please don't ruin the one great thing about shell scripting, which is that it's still possible to write one shell script that runs everywhere. Yes it's old, antiquated and quirky. It's also very convenient not to have to 1) install new tools on every system, 2) adapt a billion old scripts for a new tool, and 3) learn yet-another-new-paradigm.
I think everyone agrees with you, and they did back in say 2016 when I started https://oils.pub
They also agreed with you in the early 1990's. There are some quotes from Richard Stallman, David Korn (author of AT&T ksh), and Tom Duff (author of rc shell) here lamenting Bourne shell:
and then you also have an upgrade to YSH, a legacy-free shell, with real data structures: https://oils.pub/ysh.html
YSH solves many legacy problems, including the exact problems from the 1990's pointed out above :-)
So to the extent that you care about moving off of bash for scripting, you should probably prefer OSH and YSH to Brush
It looks like Brush aims for the OSH part (compatible), but there is no YSH part (dropping legacy)
(I may run Brush through our spec tests to see how compatible it is, but looking at number of tests / lines of code, I think it has quite some distance to go.)
[1] e.g. early this year, Koichi Murase rewrote bash arrays in OSH to use a new sparse data structure, which I mentioned in the latest blog post. Koichi is the author of the biggest shell program in the world (ble.sh), and also a bash contributor.
Well the problem is that what should be the lingua-franca in a post POSIX/Bash world?
My preference is PowerShell. It's now open source [1], it has a wide install base, and is cross-platform. It is a bit heavy and slower to start (actually takes seconds), but the cleaness of it's record-based nature versus just string parsing is infinitely refreshing.
I didn't realize fish was written in Rust, and it was my primary shell for a few years. Looks like they couldn't resist the rewrite it in Rust meme :-D
We have a decent amount of code in bash that I'd like to get working on Windows too, once Nix on Windows is ready. I'm happy to rewrite it to a better language, but if I can get a non-CygWin/MSYS2 bash-compatible shell, that's a very nice thing to try out.
(...HN formatting fail, imagine shell output showing the nixpkgs bash binary is 1.1M, the brush binary is 6.9M...)
with no prospect of further amortizing that size through shared libraries. Without shared libraries the only chance I see for rust being used to replace base system tools is with multi-call binaries a la busybox.
Hello world is really large, and it's unamusing how so much of the standard library is creamed into the resulting binary, no matter how trivial...
Do you know the current status of dynamic linking? I guess the lack of ABI stability is the big blocker, right? Probably no use in formalizing the linking bits if the goal posts keep moving. So it seems like the big problem is some committee will never complete the task... Because it will never be perfect... Something like that.
Gankra wrote a good piece about all the work involved in this years ago (specifically, what Swift had to go through to get ABI stability) <https://faultlore.com/blah/swift-abi/>
I think it's about more than just having ABI stability - the rust ecosystem is built around applications being able to demand exact micro-versions of every dependency and that falls apart when you want multiple non-cooperative applications sharing the same crate binary.
Readit News
Other than OSH, it seems to be the only shell that aims for POSIX/bash compatibility, out of dozens of alternative shells: https://github.com/oils-for-unix/oils/wiki/Alternative-Shell...
As far as I know, OSH is the most POSIX- and bash-compatible shell:
Nine Reasons to Use OSH - https://oils.pub/osh.html
If I have time, I will run this through our spec tests: https://oils.pub/release/0.29.0/test/spec.wwz/osh-py/index.h...
---
About this part: There are a number of other POSIX-ish shells implemented in a non-C/C++ implementation language
OSH is implemented in an unusual style -- we wrote an "executable spec" in typed Python, and then the spec is translated to C++.
That speeds it up anywhere from 2x-50x, so it's faster than bash on many workloads
e.g. a "fibonacci" is faster than bash, as a test of the interpreter. And it makes 5% fewer syscalls than bash or dash on Python's configure (although somehow this doesn't translate into wall time, which I want to figure out)
It's also memory safe, e.g. if there is no free() in your code, then there is no double-free, etc.
---
As mentioned on the OSH landing page, YSH is also part of the Oils project, and you can upgrade with
If you want JSON and so forth, e.g. YSH aims to be the "ultimate glue language" - https://oils.pub/ysh.htmlHow does that work in practice? Is it an arena allocator per command execution? Fixed size preallocation of space for shell variable names and values?
That was completed in 2023: Pictures of a Working Garbage Collector
https://www.oilshell.org/blog/2023/01/garbage-collector.html
https://news.ycombinator.com/item?id=34350260
There are two reasons to have a GC:
(1) The AST (aka "lossless syntax tree") is actually GRAPH - it is useful to share nodes.
I think graphs are fairly common for ASTs. Once a node can have multiple parents, then ownership becomes less clear, and errors using arenas can easily cause memory safety bugs.
For example, in Rust, I think you start using Rc<T> and so forth, which is automatic memory management at runtime.
(2) YSH is part of Oils, and it has nested dicts and lists like Python and JavaScript.
Once you have nested dicts and lists, you need GC. We actually have the GC at the "meta-level", and that (somewhat surprisingly) saves a ton of code and bugs.
It's like writing a Python/Ruby interpreter in Java or Go, and re-using the platform GC, rather than writing one specific to your language.
In particular, we don't have GC rooting, ownership, or anything like Py_INCREF/DECREF littered all over the codebase. This makes our implementation like an executable spec!
And that makes it very easy to contribute -- you write typed Python, and it's as fast as shells written in C. I think it's the best of both worlds
---
Something I've pointed out over the years, and which many people find illuminating, is
- bash doesn't have nested maps and arrays -- it only has flat ones. Therefore it doesn't need GC
- awk too - it doesn't need GC, because its data structures are limited - https://news.ycombinator.com/item?id=28785732
- make and cmake too.
I put all these "weak glue" languages in the "string-ish" category. In contrast, YSH gains A LOT of power from having real data structures, and that requires GC.
(Writing a GC was the hardest part of the project -- I think sh/awk/make/cmake left it out for a reason! Even nushell has no GC I believe. fish lacks a GC too.)
YSH has more of the power of Python/JS/Ruby, which if you look at it historically, did "replace" shell and awk for a huge set of problems. (Guido van Rossum specifically mentioned the "hole" between shell and C as a motivation for Python.)
Garbage Collection Makes YSH Different - https://www.oilshell.org/blog/2024/09/gc.html
---
On a different note, if anyone really wants a shell buildable with the Rust toolchain, it would be worthwhile to TRANSLATE Oils to Rust. This will definitely work, because Oils is translated to C++ (completed in early 2024).
You would have to write the runtime, which is around 4K lines for the garbage collector, and 4K lines for the OS bindings. That's a lot easier than writing a bash-compatible shell.
That is, Oils has about 8K lines of hand-written C++ code. Compare with bash which is 162K+ lines of C written from scratch -- it's 20x less.
I think 8K lines of unsafe code is also comparable to Rust binaries. e.g. prior to ~2018, Rust binaries used dlmalloc by default, which is 20-30K lines of C code.
(What's important is that almost all PRs modify safe code only -- it is very easy to review typed Python)
This would be a fun exercise for anybody interested in writing a GC in Rust (which is a hard challenge, with many nontrivial choices). You can write a GC, and get a shell for free, etc.
---
Also, Brush and nushell are different projects ... Oils has both things -- OSH and YSH -- compatible and new
So you actually get 2 shells for free by doing that :-P The "executable spec" strategy took a long time, but it actually worked!
I'd love to see more shell exploring things beyond POSIX. Text based stdin/stdout will always have its place, but having ways to express, serialize, and pass along data in more structured ways is quite nice.
Common worries I hear from people that were non-issues in practice:
- Not POSIX compatible: Nushell doesn't aim to replace POSIX, there's no problem with dropping back to bash to execute some shell snippets
- You need to re-learn everything: I'm not a huge fan of how the commands are organized, but I still didn't find it that difficult. nushell's prompt/readline comes with an inline help menu with fuzzy search. Hit CTRL+O to edit a command/pipeline in your IDE/editor of choice with LSP backed intellisense, type-checking and in-editor command docs/help. The syntax is very simple and intuitive.
- Just use python: Sure, but python comes with a lot of disadvantages. It's slow and uses dynamic typing. Static typing in nushell catch typos in pipelines & scripts before they execute. It also makes in-shell and IDE LSP tab-completions very accurate. Large files process quickly though it will still consume more memory if you aren't able to process all the data in a streaming fasion. It's like having jq but with autocomplete and it works on all command output & shell variables. Though if you really like python, check out Oil/OSH/YSH: https://oils.pub/
- All Unix commands output text, structured data is useless in a shell: `detect columns` (https://www.nushell.sh/commands/docs/detect_columns.html) - now it's structured. Or use `from <format>` if the command outputs CSV, JSON, INI, YAML, etc... Or don't, cause GNU tools work fine in nushell if you keep everything in text format
And there are other crazy features too.
- Write nushell plugins in your language of choice, plugins can work with structured data
- Plugins can run in the background and maintain state, nushell can automatically start a plugin when it is first used and stop the plugin when it is idle
- Data can carry metadata, e.g. binary data can carry its mime type, strings often carry metadata about which line and file the string was read from.- Closures, generators, ranges, errors/exceptions + try-catch
- Ongoing work on DAP suppprt to allow debugging scripts from your IDE
- Create your own hooks to customize how different types of data are displayed. Display structured data in table/tree form, display binary data in hex, etc...
- Collect related commands/variables into modules. Load a module knowing that you can easily unload the whole module later, module contents don't pollute global state. Variable declarations, env vars and loaded modules are scoped to the current code block and disappear after the closing bracket, lowering the odds of a name collision.
- Native support of Polars dataframes to work with even moar data
- Complex parllelism: Message-passing/actor architecture background jobs. Turn-key parallelism: transform every element of a list in parallel - `par-each` (https://www.nushell.sh/commands/docs/par-each.html)
The biggest downside of nushell is that it hasn't hit 1.0 yet so commands occasionally get renamed. Expect that you may occasionally need to tweak a script to get it working again. Definitely a pain point.
But a lot of the structured data transformation use cases I encounter, I find myself tackling in DuckDB. It's a little harder for the simplest things, but it pulls ahead quickly. Or at least it does if you need to remember SQL anyway...
Nushell on the other hand takes the (IMO more pragmatic) stance that the underlying app will most likely be writing strings to stdout and it's the shell's job to make it easy to discern the structure in those strings.
Perhaps a powershell wizard can show me that I'm wrong about this, but my feeling is that the powershell equivalent to this nushell is going to either call some external program (in addition to docker) or be quite messy:
[1] https://github.com/fish-shell/fish-shell/releases/tag/4.0.0
[2] https://fishshell.com/docs/current/design.html
1. You can do a superset of POSIX, like BASH and I think Zsh. This gives you a graceful upgrade path while maintaining backward compatibility, at the expense of being somewhat "stuck" in places. Oil is another attempt at exploring how best to use this path.
2. You can throw out POSIX totally, like fish and PowerShell. This lets you really improve things, at the expense of breaking backwards compatibility. IMHO, breaking compatibility is painful enough that it's really really hard to justify.
It's also worth pointing out that you can separate the roles of "interactive shell" and "shell for scripts". It is, for example, perfectly reasonable to use fish for interactive sessions while keeping /bin/sh around and perhaps even preferring dash as its implementation, which gives you compatibility with software while making things friendlier to users. I mean, I say this as someone who writes a lot of sh scripts and between that and years of practice my fingers expect something roughly sh-like, but I hear a lot of good things from folks who just switched their interactive shell to ex. fish.
The latest standards for POSIX.2 utilities are here:
https://pubs.opengroup.org/onlinepubs/9799919799/utilities/
I do agree with you that UNIX userland would be miles ahead of where we are now if the POSIX.2 standard could be cajoled out of the '80s.
I strongly disagree with the notion of only learning one shell language "because what if I telnet into an ancient Sun box and Fish isn't available?" In exactly the same way, I don't exclusively write my programs in C in case some remote host might not have Python or Rust or Fish some day. I'll cross that bridge when I come to it, but in the mean time I want to use something that makes me happy and productive.
But please don't ruin the one great thing about shell scripting, which is that it's still possible to write one shell script that runs everywhere. Yes it's old, antiquated and quirky. It's also very convenient not to have to 1) install new tools on every system, 2) adapt a billion old scripts for a new tool, and 3) learn yet-another-new-paradigm.
They also agreed with you in the early 1990's. There are some quotes from Richard Stallman, David Korn (author of AT&T ksh), and Tom Duff (author of rc shell) here lamenting Bourne shell:
https://www.oilshell.org/blog/2019/01/18.html#slogans-to-exp...
A problem with using a Bourne shell compatible language is that field splitting and file name generation are done on every command word
nobody really knows what the Bourne shell’s grammar is
---
But there is a "collective action" problem. Shell was the 6th FASTEST growing language on Github in 2022: https://octoverse.github.com/2022/top-programming-languages
I imagine that, in 2025, there are MORE new people learning POSIX shell/bash, than say any other shell here: https://github.com/oils-for-unix/oils/wiki/Alternative-Shell...
Because they want to get work done for the cloud, or embedded systems, or whatever
Also, LLMs are pretty good at writing shell/bash!
---
Oils is designed to solve the legacy problem. OSH is the most bash-compatible shell in the world [1]:
https://oils.pub/osh.html
and then you also have an upgrade to YSH, a legacy-free shell, with real data structures: https://oils.pub/ysh.html
YSH solves many legacy problems, including the exact problems from the 1990's pointed out above :-)
So to the extent that you care about moving off of bash for scripting, you should probably prefer OSH and YSH to Brush
It looks like Brush aims for the OSH part (compatible), but there is no YSH part (dropping legacy)
(I may run Brush through our spec tests to see how compatible it is, but looking at number of tests / lines of code, I think it has quite some distance to go.)
[1] e.g. early this year, Koichi Murase rewrote bash arrays in OSH to use a new sparse data structure, which I mentioned in the latest blog post. Koichi is the author of the biggest shell program in the world (ble.sh), and also a bash contributor.
https://github.com/oils-for-unix/oils/wiki/The-Biggest-Shell...
My preference is PowerShell. It's now open source [1], it has a wide install base, and is cross-platform. It is a bit heavy and slower to start (actually takes seconds), but the cleaness of it's record-based nature versus just string parsing is infinitely refreshing.
[1] https://github.com/PowerShell/PowerShell
https://github.com/fish-shell/fish-shell/tree/c2eaef7273c555...
vs the C++
https://github.com/fish-shell/fish-shell/tree/d9d3557fcfbce1...
Initial motivation: https://github.com/fish-shell/fish-shell/pull/9512#issuecomm...
I switched to the beta on the day it was released and haven't had one single issue with it. That was the smoothest rewrite I've ever seen.
We have a decent amount of code in bash that I'd like to get working on Windows too, once Nix on Windows is ready. I'm happy to rewrite it to a better language, but if I can get a non-CygWin/MSYS2 bash-compatible shell, that's a very nice thing to try out.
https://frippery.org/busybox/index.html
This is actually the Almquist shell with many bashisms brought in (no arrays though).
Edit: The ADA port below might interest you.https://github.com/AdaCore/gsh
https://archive.fosdem.org/2019/schedule/event/ada_shell/
you'd probably want the rest of the programs, too. bash isn't too useful on its own. you can also find those on the same website
(...HN formatting fail, imagine shell output showing the nixpkgs bash binary is 1.1M, the brush binary is 6.9M...)
with no prospect of further amortizing that size through shared libraries. Without shared libraries the only chance I see for rust being used to replace base system tools is with multi-call binaries a la busybox.
Hello world is really large, and it's unamusing how so much of the standard library is creamed into the resulting binary, no matter how trivial...
Do you know the current status of dynamic linking? I guess the lack of ABI stability is the big blocker, right? Probably no use in formalizing the linking bits if the goal posts keep moving. So it seems like the big problem is some committee will never complete the task... Because it will never be perfect... Something like that.
Is it faster, but otherwise identical to bash? And if yes, are there any sorts of benchmarks?
Implementation language: Rust
That strikes me as enough for many use-cases.
So I would run WSL in powershell, and Brush in WSL?