Something very similar to this had been done many times in third party libraries. None of those have become hugely popular, including none quite compelling me personally to do more than try them out as toys.
It's too bad, in a way, since I love bash and use it all the time when it seems easier than Python. Your library is 100% certainly not going to become part of the standard library unless it can first become popular as a third party tool. If it does become popular that way, I wouldn't put it's odds of eventual soon to the standard library as higher than 5-10%. But that doesn't really matter, widespread use his 'pip install' world be a good thing in itself. On Sat, Aug 10, 2019, 7:52 AM Thiago Padilha <tpadilh...@gmail.com> wrote: > Python is often used a shell scripting language due to it being more > robust than traditional Unix shells for managing complex programs, but > it is significantly more verbose than Bash & friends for doing common > shell scripting tasks such as writing pipelines and redirection . > > I propose adding an idiomatic shell scripting API that uses Python > operator overloading in a way that allows invoking commands in a > Bash-like way. > > A fully working implementation (which I've been using in my personal > scripts) can be found at https://github.com/tarruda/python-ush/. Here > I will describe the basics of the API, more details in the github > README.rst (which is also a doctest for the project). > > Here's how one can create commands: > > >>> from shell import Shell > >>> sh = Shell() > >>> cat = sh('cat') > >>> ls = sh('ls') > >>> sort = sh('sort') > # or something like this: > >>> cat, ls, sort = sh('cat', 'ls', 'sort') > > The Shell class is the entry point of the API and it is used as a > factory for Command objects. For convenience we can add a builtin > Shell instance which is a also module from where commands can be > quickly imported from (idea taken from sh.py > http://amoffat.github.io/sh/): > > >>> from shell.sh import cat, ls, sort > > We can construct more complex commands by calling it with certain > arguments: > > >>> ls('-l', '-a', env={'LANG': 'C.UTF-8'}) > > And we can invoke the command by calling it without arguments: > > >>> ls() > # or > >>> ls('-l', '-a', env={'LANG': 'C.UTF-8'})() > > Invoking the command returns a tuple with the status code: > > >>> ls() > (0,) > > The are more ways to invoke a command other than calling it without > arguments. One such example is by iterating through it, which > automatically takes care of piping the output back to python: > > >>> files = [] > >>> for line in ls: > ... files.append(line) > > Pipelines can be easily created with the `|` operator: > > >>> ls = ls('--hide=*.txt', env={'LANG': 'C.UTF-8'}) > >>> sort = sort('--reverse') > >>> ls | sort > ls --hide=*.txt (env={'LANG': 'C.UTF-8'}) | sort --reverse > > Everything that can be done with Command objects, can also be done > with Pipeline objects: > > >>> (ls | sort)() > (0, 0) # single commands return a tuple to make the return value > compatible with Pipelines > >>> list(ls | sort) > [u'tests', u'setup.cfg', u'pytest.ini', u'bin', u'README.rst'] > > We also use the Pipeline syntax for redirecting input/output. > > # piping to a filename string redirects output to the file > >>> (ls | sort | '.stdout')() > (0, 0) > >>> str(cat('.stdout')) > 'tests\nsetup.cfg\npytest.ini\nbin\nREADME.rst\n' > # piping from a filename string redirects input from the file > >>> str('setup.cfg' | cat) > '[metadata]\ndescription-file = > README.rst\n\n[bdist_wheel]\nuniversal=1\n' > > This is the basic idea. The current implementation only supports the > classic subprocess API, but I can probably make it compatible with > asyncio (to create async shells which spawns commands compatible with > `await`). > > Thoughts? Is it worth writing a PEP for this? > > Best regards, > Thiago. > _______________________________________________ > Python-ideas mailing list -- python-ideas@python.org > To unsubscribe send an email to python-ideas-le...@python.org > https://mail.python.org/mailman3/lists/python-ideas.python.org/ > Message archived at > https://mail.python.org/archives/list/python-ideas@python.org/message/NZSFQXBXCSRUR7HMJFEQBDFBQFN4P3SH/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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