Develop Reference

VS Code trying to run .../Activat.ps1 in cmd terminal

I'm using VS Code for a Python project using a virtualenv. I switched my deafult terminal from powershell to cmd as VS Code was not happy executing powershell scripts.
Now when I open a terminal in my project it opens cmd (as desired), but automatically tries tor run .../Scripts/Activate.ps1, which it doesn't like. I want it to run .../Scripts/Activate.bat as we are in cmd. Runnning it manually for now, but would be nice if I didn't have to.
No doubt there is a setting somewhere to change this, but I cannot find it. Any ideas?

This is a problem related to the Python extension, it should be fixed in the last update.
You can get some information from here.

iPython automatically at launch in Visual Studio Code on Os X

I would like that iPython run automatically when I launch VSC instead of typing ipython and press enter in the terminal. The answer here How to set ipython/jupyter as the default python terminal for vscode? doesn't work as it is for windows but it shouldn't be really different. Also, is there something similar to the 'Execute' button in Spyder instead of typing %run filename ? Thanks !

I presume you mean you want to run the "Python Interactive Window" and not just an iPython console on startup
There is currently no way to run it on startup. At least no way without writing another extension that would run a command when opening a workspace. It would be simple for us to add one though. Probably a workspace setting. Can you log an issue here:
https://github.com/Microsoft/vscode-python/issues/new
For you second question, 'Execute' in spyder, we have 'Run Current File in Python Interactive Window'. This works on any python file. You can get to it through the context menu on a file or through the command palette.

Sadly the nice workflow of spyder is not provided by any official extension at the moment (as far as I know).
But you can implement the basics easily on your own by writing an extension. Even with no experience in TypeScript you can quickly build an extension which starts an IPython console as soon as you open a python file. I also managed to execute a startup script which implements the runfile method. VS Code also allows keybindings for your functions, so that you can almost work like you can with spyder.
Spyder modified the IPython terminal quite a bit though, so it won't feel exactly the same. But after all, everything there is open source so you could implement it yourself, which is what I'm trying to do in my free time.

Python in VSCode: How do you run a previous command?

I'm kind of new to software development. Outside of VSCode, I can open up a terminal (let's say PowerShell), run python in it, type in a command (like 2+2), be able to click the up arrow key to find my previous command so that I can run it again.
If I run PowerShell in VSCode and do the same thing, nothing happens when I click the up arrow where I would expect my previous command to be cycled.
Is this a problem with my Python or VSCode? I've been looking for a solution for this but haven't found many useful topics on this.

This was going to just be a comment but its too long. Sorry it isn't more informative than it is. This is kind of an odd problem because VSCode isn't a true IDE. It doesn't have its own shell and just hijacks your powershell or bash terminal, depending on which OS you are using. You should be able to use your up and down arrows just like you can in powershell. I have tested it on my own VSCode installation and it works fine for me. If it's a problem, it's not with python, since VSCode will interact with the terminal the same way no matter which language you are using it for, so its probably with VSCode or your terminal. I have heard of others having issues with up arrow autocomplete in bash, so if you are connecting to a bash terminal that could be it, but I've never heard of it glitching in powershell. I'd say check which terminal you are using, see if the problem persists when you change terminals, and try reinstalling VSCode if it does. Past that, I don't know what to tell you.

I found a work-around. For me, neither git bash, nor PowerShell allowed up/down arrows for history switching within a python shell. So here it goes.
Ctr-Shift-P opens VSCode commands
Python: Create Terminal does not actuallt start python, but it does launch powershell in a mode that will enable us to succeed
py starts python shell with working up/down arrows!

launch external shell python instance in shell from python

I'd like to call a separate non-child python program from a python script and have it run externally in a new shell instance. The original python script doesn't need to be aware of the instance it launches, it shouldn't block when the launched process is running and shouldn't care if it dies. This is what I have tried which returns no error but seems to do nothing...
import subprocess
python_path = '/usr/bin/python'
args = [python_path, '&']
p = subprocess.Popen(args, shell=True)
What should I be doing differently
EDIT
The reason for doing this is I have an application with a built in version of python, I have written some python tools that should be run separately alongside this application but there is no assurance that the user will have python installed on their system outside the application with the builtin version I'm using. Because of this I can get the python binary path from the built in version programatically and I'd like to launch an external version of the built in python. This eliminates the need for the user to install python themselves. So in essence I need a simple way to call an external python script using my current running version of python programatically.
I don't need to catch any output into the original program, in fact once launched I'd like it to have nothing to do with the original program
EDIT 2
So it seems that my original question was very unclear so here are more details, I think I was trying to over simplify the question:
I'm running OSX but the code should also work on windows machines.
The main application that has a built in version of CPython is a compiled c++ application that ships with a python framework that it uses at runtime. You can launch the embedded version of this version of python by doing this in a Terminal window on OSX
/my_main_app/Contents/Frameworks/Python.framework/Versions/2.7/bin/python
From my main application I'd like to be able to run a command in the version of python embedded in the main app that launches an external copy of a python script using the above python version just like I would if I did the following command in a Terminal window. The new launched orphan process should have its own Terminal window so the user can interact with it.
/my_main_app/Contents/Frameworks/Python.framework/Versions/2.7/bin/python my_python_script
I would like the child python instance not to block the main application and I'd like it to have its own terminal window so the user can interact with it. The main application doesn't need to be aware of the child once its launched in any way. The only reason I would do this is to automate launching an external application using a Terminal for the user

If you're trying to launch a new terminal window to run a new Python in (which isn't what your question asks for, but from a comment it sounds like it's what you actually want):
You can't. At least not in a general-purpose, cross-platform way.
Python is just a command-line program that runs with whatever stdin/stdout/stderr it's given. If those happen to be from a terminal, then it's running in a terminal. It doesn't know anything about the terminal beyond that.
If you need to do this for some specific platform and some specific terminal program—e.g., Terminal.app on OS X, iTerm on OS X, the "DOS prompt" on Windows, gnome-terminal on any X11 system, etc.—that's generally doable, but the way to do it is by launching or scripting the terminal program and telling it to open a new window and run Python in that window. And, needless to say, they all have completely different ways of doing that.
And even then, it's not going to be possible in all cases. For example, if you ssh in to a remote machine and run Python on that machine, there is no way it can reach back to your machine and open a new terminal window.
On most platforms that have multiple possible terminals, you can write some heuristic code that figures out which terminal you're currently running under by just walking os.getppid() until you find something that looks like a terminal you know how to deal with (and if you get to init/launchd/etc. without finding one, then you weren't running in a terminal).

The problem is that you're running Python with the argument &. Python has no idea what to do with that. It's like typing this at the shell:
/usr/bin/python '&'
In fact, if you pay attention, you're almost certainly getting something like this through your stderr:
python: can't open file '&': [Errno 2] No such file or directory
… which is exactly what you'd get from doing the equivalent at the shell.
What you presumably wanted was the equivalent of this shell command:
/usr/bin/python &
But the & there isn't an argument at all, it's part of sh syntax. The subprocess module doesn't know anything about sh syntax, and you're telling it not to use a shell, so there's nobody to interpret that &.
You could tell subprocess to use a shell, so it can do this for you:
cmdline = '{} &'.format(python_path)
p = subprocess.Popen(cmdline, shell=True)
But really, there's no good reason to. Just opening a subprocess and not calling communicate or wait on it already effectively "puts it in the background", just like & does on the shell. So:
args = [python_path]
p = subprocess.Popen(args)
This will start a new Python interpreter that sits there running in the background, trying to use the same stdin/stdout/stderr as your parent. I'm not sure why you want that, but it's the same thing that using & in the shell would have done.

Actually I think there might be a solution to your problem, I found a useful solution at another question here.
This way subprocess.popen starts a new python shell instance and runs the second script from there. It worked perfectly for me on Windows 10.

You can try using screen command
with this command a new shell instance created and the current instance runs in the background.
# screen; python script1.py
After running above command, a new shell prompt will be seen where we can run another script and script1.py will be running in the background.
Hope it helps.

Python IDE on Linux Console

This may sound strange, but I need a better way to build python scripts than opening a file with nano/vi, change something, quit the editor, and type in python script.py, over and over again.
I need to build the script on a webserver without any gui. Any ideas how can I improve my workflow?

put this line in your .vimrc file:
:map <F2> :w\|!python %<CR>
now hitting <F2> will save and run your python script

You should give the screen utility a look. While it's not an IDE it is some kind of window manager on the terminal -- i.e. you can have multiple windows and switch between them, which makes especially tasks like this much easier.

You can execute shell commands from within vim.

Using emacs with python-mode you can execute the script with C-c C-c

you can try ipython. using its edit command, it will bring up your editor (nano/vim/etc), you write your script, and then on exiting you're returned to the ipython prompt and the script is automatically executed.

When working with Vim on the console, I have found that using "tabs" in Vim, instead of having multiple Vim instances suspended in the background, makes handling multiple files in Vim more efficient. It takes a bit of getting used to, but it works really well.

You could run XVNC over ssh, which is actually passably responsive for doing this sort of thing and gets you a windowing GUI. I've done this quite effectively over really asthmatic Jetstart DSL services in New Zealand (128K up/ 128K down =8^P) and it's certainly responsive enough for gvim and xterm windows. Another option would be screen, which lets you have multiple textual sessions open and switch between them.

There are actually 2 questions. First is polling for a console IDE for python and the second is a better dev/test/deploy workflow.
For while there are many ways you can write python code in the console, I find a combination of screen, vim and python/ipython is the best as they are usually available on most servers. If you are doing long sessions, I find emacs + python-mode typically involves less typing.
For a better workflow, I would suggest setting up a development environment. You can easily setup a Linux VM on your desktop/laptop easily these days - there isn't a excuse not to even if it's for hobby projects. That opens up a much larger selection of IDEs available to you, such as:
GUI versions of VI and friends
Remote file editing with tramp and testing locally with python-mode inside Emacs
http://www.netbeans.org
and of course http://eclipse.org with the PyDev plugin
I would also setup a SCM to keep track of changes so that you do
better QA and use it to deploy tested changes onto the server.
For example I use Mercurial for my pet projects and I simply tag my repo when it's ready and update the production server to the tag when I deploy. On the devbox, I do:
(hack hack hack, test test test)
hg ci -m 'comment'
hg tag
hg push
Then I jump onto the server and do the following when I deploy:
hg update
restart service/webserver as needed

Well, apart from using one of the more capable console editors (Emacs or vi would come to mind), why do you have to edit it on the web server itself? Just edit it remotely if constant FTP/WebDAV transfer would seem to cumbersome.
Emacs has Tramp Mode, gedit on Linux and bbedit on the Mac support remote editing, too. Probably quite a large number of other editors. In that case you would just edit in on a more capable desktop and restart the script from a shell window.

For what it's worth, VIM alone can do the same tasks as previously posted. I have had the same problem with testing Python from the command line.
My solution was to use the screen command. I split screens vertically, I run Python in one instance of a shell, and on the second screen, I usually edit Python code with VIM.
Command to install screen:
sudo apt-get install screen
The screen package has a bit of a learning curve but there isn't any mystery if you can remember the "Ctrl-Alt ?" command that contains all knowledge.
No GUI is required!