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Why Create a New Unix Shell?

73 points| tux1968 | 5 years ago |oilshell.org | reply

62 comments

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[+] earthscienceman|5 years ago|reply
It's only tangential but switching to fish shell made me about 3 times more productive. Being able to easily recall commands, to have completions displayed as I type, and to have interactivity be a first class citizen of the environment... made working in the shell so so so so much nicer.

Fish has its own quirks, some of which seem unnecessary, but it was a godsend. There is definitely still room for improvement of the old tools, a. lot. of. room.

[+] flohofwoe|5 years ago|reply
I switched from fish to zsh once I found this plugin:

https://github.com/zsh-users/zsh-autosuggestions

Now zsh feels just like fish, but with bash-compatible syntax (which was the main day-to-day problem I had with fish, otherwise it's fine, but except for the auto-suggestions I didn't really use any special fish features).

[+] gdsimoes|5 years ago|reply
I was always reluctant to change my shell, but recently I switched to fish and It’s been a pleasure from day one. I wish I did it sooner.
[+] socialdemocrat|5 years ago|reply
I am a huge fan of fish. Oil shell seems kind of different in aim from fish. Fish is trying primarily to be a great interactive shell and have code which is easy to understand but not necessarily compact of efficient to write. But for me it doesn’t matter. For longer things I use Julia or Go anyway.
[+] treve|5 years ago|reply
It always surprises me that people get so much productivity gain out of their editors, shells and keyboards and such.

I write maybe a few dozen lines of code on a good day.

[+] chovybizzass|5 years ago|reply
How does fish compare to zsh? I just switched from bash to zsh and am loving it.
[+] CameronNemo|5 years ago|reply
My least favorite fish quirk is that you cannot use stty to remap Ctrl-C. You need to use stty in another shell, then exec into fish to remap it.
[+] andrewchambers|5 years ago|reply
Interesting, it seems a 3x productivity boost to all programmers and admins would be a no brainer for the industry.
[+] gorgoiler|5 years ago|reply
Oil looks interesting. The documentation is compelling.

I sleep at night by writing stoic bash. If I encounter anything unexpected in a script I don’t try to handle it, I just report it and then crash.

Most of the bash contortions I’ve seen in my life happen when people (myself included) have tried to handle error conditions or ill specified inputs, gracefully.

A bash script is like a pre-flight checklist: a list of things that should work to get something going. Most bash scripts are like this: in general they are sequences of commands to change the system from one good state to another, not to recover it from a bad state.

In the analogy: if something is not ok with your aircraft it’s beyond the scope of the pre flight check to fix it. Don’t use the checklist as a way of trying to automatically detect what the error is in order to fix it.

[+] waynesonfire|5 years ago|reply
Great analogy. This is exactly how I use bash and have never thought to articulate it this way.
[+] lawl|5 years ago|reply
I think the author realized something important. There's the bash as a CLI users and bash as a scripting language users. I'm firmly in camp one and I think it's an important difference to realize.

I don't want my CLI to be a REPL for a scripting language. It's something I really disliked about PowerShell when I tried it. It just felt like a dotnet scripting language and not like a CLI.

If Oil provides a scripting interface with structured types etc. I'm all for it. I just don't want to have to deal with it when using the shell interactively. I love it when writing scripts and programs, but not for interactive shell use.

[+] giancarlostoro|5 years ago|reply
Reason I use fish is purely for OOTB shell defaults that are nice. I wouldnt script for Fish though its not a standard shell on most OS.
[+] quantified|5 years ago|reply
What if the language is “shell”-ish? Reading the piece, the idea of shell as a REPL seemed attractive.
[+] ahurmazda|5 years ago|reply
Others' experiences may vary but personally speaking I have to write a fair amount of shell scripts that run on a range of machines, networks etc. At best its a pita to change shell on these ephemeral boxes, worst case its out of my control.

The lowest common denominator ends up being the good ol' bash (or sh)! Sure fish/oil is nice but quite a bit of mental gymnastics to keep them all straight in my head.

[+] chubot|5 years ago|reply
That's reasonable, but Oil can still be useful to you as a dev tool, since it implements a very large and sane subset of bash. Some details here:

http://www.oilshell.org/why.html

And something I just released is a better "set -x", which no other shell has:

https://www.oilshell.org/release/0.8.7/doc/xtrace.html

So you could debug your programs with Oil if bash tracing isn't enough (which it often isn't for me).

Oil is also very easy to build and install -- all you need is a compiler, a shell, and make, and make will probably go away at some point.

[+] throwawayboise|5 years ago|reply
This is why I use the default shell on whatever platform I'm working on. I want to know that my work does not first dependon on installing an alternate shell (often not possible, depending on the environment).
[+] m463|5 years ago|reply
I would like to know other people's habits.

for example, I always close browser windows and only keep a few tabs open at once, and then found out I was weird and many people keep huge amounts of tabs around.

My personal habit is to use bash, and always write shell scripts with #!/bin/sh as the first line.

Thing is - I've haven't tried other shells (since I was a student) because of "linux superstition". Same superstition that chooses filenames without spaces and prevents putting "." in your path.

Thing is - I think maybe decoupling the user interface from the scripting language should be more of a thing. People don't have as much trouble switching out their terminal emulator (a way of taking up the slack).

Maybe the way to a better UI while maintaining compatibility would be to choose a good "user interface" shell and maybe exporting SHELL=/bin/bash so scripts run?

[+] saagarjha|5 years ago|reply
> GNU bash is the most popular shell implementation in the world. It was first released in 1989, and implements the POSIX standard plus many extensions. It's the default shell on most Linux distributions, runs on BSD Unix variants, used to ship on Mac OS X, and runs on Windows.

Note that macOS still ships bash.

[+] edgyquant|5 years ago|reply
I haven’t had a Mac in a few years but iirc they ship zsh* nowadays not bash
[+] peter_d_sherman|5 years ago|reply
Greetings!

First off, any person who would write either a language or a shell, now or in the future, should read your page, and in fact, should read everything about your Oil shell/language...

It's a laudable effort!

This page is going to my HN favorites, for future review.

What follows next are my thoughts about selected excerpts of text on the page (please don't interpret as criticism, that's not the intent):

>"You can think of a Unix shell in two ways:

1. As a text-based user interface. You communicate with the operating system by typing commands.

2. As a language. It has variables, functions, and loops. Shell programs are text files that start with #!/bin/sh."

[...]

>"Are you reinventing Perl?

It's true that Perl is closer to shell than Python and Ruby are. For example, the perl -pie idiom can take the place of awk and sed. However, Perl isn't an acceptable shell either:

o It doesn't have true pipelines (of processes). I believe you have to "shell out" for this.

o It doesn't have a concept of file descriptor state. How do you write the equivalent of my_shell_func 2> err.txt, where my_shell_func can invoke both functions and external commands?

o Perl has a function called grep(), but the real grep is better for many problems."

PDS: This touches upon a historic problem, which is basically that either:

A) Shell designers work their way "up" to a programming language, in which case some elegant programming language features are either not thought about, or not thought deeply enough about, and thus either not implmented, or implemented poorly / "non-orthagonally", AKA a "Kludge".

Or:

B) Language designers work their way "down" to supporting shell commands / a shell subsystem -- in which case some elegant shell features are either not thought about, or not thought deeply enough about, and thus either not implmented, or implemented poorly / "non-orthagonally", AKA a "Kludge".

Also, languages are typically too heavy in what they require typed for shell-scripters, and shells are typically too light in what they allow (and error checking/debugging features) for programmers writing large programs...

If someone were to design the most ideal programming language which also can be used for shell scripting, they'd have to look at things from both perspectives, and they'd have to create a language/shell -- completely balanced "down the middle" between these two paradigms...

Perhaps the Oil shell/programming language -- is, or will become that middle line...

To that extent, I wish you a lot of luck!

If I were going to go down this path, I'd look at "first principles" (Elon Musk):

The greatest differentiator between shell commands and lines of code in most programming languages is the point you alluded to in your comparison with Perl:

"o It doesn't have true pipelines (of processes). I believe you have to "shell out" for this."

In other words, in most programming languages (unless you are using threads), you are guaranteed linear execution.

In a Unix shell -- because you can run multiple commands that may take varying amounts of time to complete, this guarantee is no longer present...

That would be the fundamental thing to keep in mind when writing this future language/shell...

(A good program to test when writing this language would be a Web-server -- where the base server is a single script, and then when it detects a connection, passes this over to either a single separate command-line invoked Unix program or script comprising multiple such Unix programs linked with pipes, but the central "server" script has to handle a whole lot of simultaneous I/O from multiple such separate programs (it centralizes database access!), and do this in a simple way that script programmers would be comfortable with, while guaranteeing the correct data flows...)

Anyway, wishing you luck in this endeavor!

[+] chubot|5 years ago|reply
(author here) Thanks for the comment! I do think you hit on something interesting, and it partly explains why the project is so big :)

To me, shell and Python/JS feel kind of similar, and that was sort of the thesis at the start of the project.

But if you just incrementally add features to Bourne shell, you basically get Korn shell, which is where bash got all the "bashisms" that people don't like.

This paper was surprising to me; the proprietary AT&T ksh was used for GUIs and so forth, AND it was embeddable like Lua:

http://www.oilshell.org/archive/ksh-usenix.pdf

[ksh] has the capabilities of perl and tcl, yet it is backward compatible with the Bourne shell. Applications of up to 25,000 lines have been written in ksh and are in production use.

Much of the impetus for ksh–93 was wksh, which allows graphical user interfaces to be written in ksh.

It's a lot more work to make something like Python or JS! Garbage collection is one issue; shells don't have it because they don't have recursive compound data structures or true functions.

So I would say that ksh "failed" because it took a lot of shortcuts. Perl, Python, Ruby, JS, and PHP won. So with Oil I also am upgrading shell, but it was a lot more work since I wanted to make it like the latter languages. It wasn't obvious at the outset how different these things are!

So in a sense Oil is upgrading shell to be more like the languages that won, which I still think is a good idea. It's weird that every computer boots to into a programming language REPL, but you're discouraged from learning it because it sucks. There's no reason that language shouldn't be a good one.

---

Yes pipelines are a big deal and the runtime is solid now so they can be enhanced. Ideas here, feel free to chime in: https://github.com/oilshell/oil/issues/843 :)

[+] crb002|5 years ago|reply
Performance or correctness. Giving bash/zsh a performant hash-table would trivially empower them without boiling the ocean.
[+] wpietri|5 years ago|reply
This reminds me: why isn't there a good Python shell? Something with, as the author says, a "domain-specific language for dealing with concurrent processes and the file system", but otherwise basically Python? I'm sure people must have tried, so I guess there are fundamental incompatibilities between the two?
[+] blackrock|5 years ago|reply
Sometimes I want a more interactive shell. With the native ability to display graphics and view html and PDFs and other docs, without opening a separate GUI program.
[+] chubot|5 years ago|reply
Yeah I hope people will build stuff like that on top of Oil. Hopefully this year the embedding story will become clearer, and progress can be made on top.

Some notes here about interactive shell ideas: https://github.com/oilshell/oil/wiki/Interactive-Shell

Some people might think Oil is sort of a text-only or retro project ... but it really isn't, it's a SPEED project. I use shell because it's the fastest to get certain things done.

But other things are faster when done with GUIs. Actually I wrote the last 5 or 6 blog posts in https://stackedit.io because copying and pasting huge swaths of text and links and images is faster with the mouse!

I am a die-hard Vim person for code, but I realized that "thinking and writing" is aided by the mouse and by rich GUIs (but not slow ones, which is hard!). Previewing hyperlinks is also very important.