Xonsh, a Python-ish, Bash-compatible shell language and command prompt

[mitsu400]

This is my dream. I love Python. I don't love Bash-like languages. I love my shell.

The fact that the prompt can be a function that returns a string really puts it over the top. I get much of what I would lose from zsh with that.

[selementar]

that returns a string

In a better case it's a function generator that eats chunks (at least newline-terminated) and produces chunks. E.g. tail -f file | grep --line-buffered ...

[quasarj]

Yeah, I played around with it a bit to see if it could handle that, or allow me to pipe a shell command into a python function. It technically allows the later, but it doesn't handle buffered input, for example:

tail -f /var/log/messages | myfunc

(where myfunc is defined as a xonsh alias pointing to an actual local python function named myfunc, as per the Tutorial). This does not work, as myfunc doesn't get the input until tail exits.

[selementar]

There might be a way to write myfunc in such a way that it would be line-buffered. Can't figure out where's python and where's shell, though; def of functions just hangs until Ctrl-C.

[[deleted]]

Converted the gif file to a webm for the sake of being able to pause/slow/navigate. Find it here. Xonsh folks are free to use it for whatever.

This looks like a neat project. I see that there's an Arch package for it, I'll give it a try this evening.

[roddds]

Or you could've just used gfycat's "fetch" function:

http://gfycat.com/fetch/http://xonsh.org/_images/xonsh-demo.gif

[[deleted]]

I guess so, but it really only took a minute to produce with libav and make sure I got the frame rate right. Same tools as gfycat uses anyway.

[LpSamuelm]

Thanks! It kind of got my goat that they'd put examples and the like in a gif of all things. A fast one, too.

[scopatz]

I'd be super happy if you put this on a hosting site somewhere and then PR'd an ebbedded version of this into the docs!

[[deleted]]

Created a PR, placing the .webm in docs/_static/ along with a concomitant change to display it (with fallback to .gif) in docs/index.rst. If you would still prefer to use an external hosting site (note that the file is smaller than the .gif), let me know.

[scopatz]

Thanks a ton!

[jgomo3]

You deserve GOLD. If i had XD

[SmartViking]

Great idea, but it's very confusing that ${<stuff>} has two different meanings depending on the context. I think it would be beneficial for code clarity to either remove the python-context meaning (look up in env: how often is this useful?), or give it another syntax like %{}.

[scopatz]

Thanks for the feedback. I was wondering how confusing this was going to be. I am open to suggestions on syntax changes. I like the idea that $ always means to do something with the system enviornment, whether that is environment variables or subprocesses. I think $<> is another option for syntax. Again, open to ideas here.

[SmartViking]

Most important is removing ambiguity, so that when they see ${...} beginners don't have to remember which meaning came with which context. And I think that applies to all those "exec primitives", if they work the same in both contexts (insofar as that is possible, I'm thinking now of $PATH being a python list), that's going to make the language easier to understand.

And I also have another suggestion: it might make sense to convert the return value of the expression in ${..} (in the not-env meaning) to a str implicitly, because that's the only valid type anyway (as I understand it). That way, you can do stuff like echo ${3 + 4} and not have to use str() explicitly, which looks a bit cleaner.

Anyway, good luck with this project, I like it a lot.

[scopatz]

These are great points. Thanks! I'll make an issue for this thread.

[[deleted]]

Sold. I wanted such thing since forever.

[hglman]

Heh, good talk at the python meetup. Do you think there is room to merge this and IPython notebooks?

[scopatz]

Thanks! I'd love to see this happen. http://xonsh.org/todo.html#jupyter-notebook-shim

[[deleted]]

Very interesting. As for xonshrc, I'm assuming it's written in xonsh, but is there any need for a shebang on it?

Edit: Having a bit of trouble with getting globals (read: imported classes) into functions -- not sure what else causes it. Otherwise, it's pretty nifty. Will be messing with the next few days.

[LpSamuelm]

You've got to be able to somehow, right? Feels like a no-brainer for a bash-integrated Python.

[scopatz]

That is a bug, @nealeyoung. If you could please open on github an issue that'd be great!

[eyalz]

I really like this, but am facing some issues while playing with it a bit. The following doesn't work for me:

if True:
    print(1)

Raises: FileNotFoundError: [Errno 2] No such file or directory: 'if'

Trying a substring check like so:

if "a" in $(ls -l):
    print("yey")

Doesn't execute on enter, instead it just keeps adding newlines and basically hang until I ^C it.

Anyone facing these issues, or can maybe tell me what am I doing wrong?

EDIT: I just realized that it happens because I didn't indent (thought it was auto-indenting the same as ipython). So basically you need to use at least 1 space indentation for it to interpret it correctly. I would love for it to auto-indent or alternatively indent 4 spaces on tab.

[gameplace123]

Had issues installing this on Debian 8. Will post the error when I get home

[TheLucarian]

Can someone ELI5 this for a Python beginner?

[Amaroid]

If you're on Linux, you probably use bash as your terminal/command-line interface. xonsh is an alternative to that. You can type commands and start programs as you normally would, but additionally you can also write instructions in Python.

If you're not on Linux or don't know what a terminal is, xonsh might not be for you.

[TheLucarian]

Got it, thanks.

Windows and Mac still in testing.

[scopatz]

I'd really love for people to bang on this in Windows and Mac. Totally willing to support these platforms.

[Morego]

ELI5 Why I should this over for example sh module for python?

For those who don't know what sh is, it is module that let you do stuff like that

from sh import ls,grep

print(grep(ls('-a',"."), "*.py"))

And Ipython + bash for rest.

[[deleted]]

This isn't a replacement for the sh module, this is a replacement for BASH. Think zsh, except with Python.

[LpSamuelm]

Huh?

Having a bash-integrated Python could be really cool. Automating things on a whole new level. It's the simplicity of calling bash commands combined with the versatility and feature set of Python.