One more thing. In your directory tree on the USB stick, it's best to
create the directories PythonX.Y/site-packages in the location used for
PYTHONUSERBASE. If you install Python 3.7, X.Y will be 3.7. This is where
Python will look for *.pth files(if you use them to set paths), it is where
you would put a site-customize directory if you use one, and apparently
occasional packages will use the directory during install or operation.
On Monday, May 11, 2020 at 11:55:01 PM UTC-4, Thomas Passin wrote:
>
> There used to be a portable app type package for Python so that it could
> be run from a USB stick and used on different computers. But no longer. I
> thought it would be interesting to see what would be involved in setting
> one up. This is for Windows. I'm sure it could be adapted for Linux
> without much trouble.
>
> First of all, the standard Python installer will install to any drive,
> including a usb stick. That's easy. Your want to install for all users so
> that there won't be a problem using it on some computer where you are not
> the specific user you installed for. But that's not the end of it.
>
> You have to take care of at least two things, if you really want to be
> portable:
>
> 1. Where python will look for configuration and settings files, the
> site-customize location, .pth files, etc. There is an environmental
> variable to use for this: PYTHONUSERBASE. You can find where it is on
> your current Python installation:
>
> >>>import site
> >>> site.getuserbase()
> 'C:\\Users\\tom\\AppData\\Roaming\\Python'
> >>> print(site.getsitepackages())
> ['C:\\Users\\tom\\AppData\\Local\\Programs\\Python\\Python38',
> 'C:\\Users\\tom\\AppData\\Local\\Programs\\Python\\Python38\\lib\\site-packages']
> >>>
>
> You need to set the user base so that it is on your usb stick.
>
> 2. Leo will look for some of its files, like its .leo/db directory, its
> user name file, and the standard workbook.leo file, in
> os.path.expanduser('~'):
>
> >>> import os
> >>> os.path.expanduser('~')
> 'C:\\Users\\tom'
>
> You need to change this to point to the USB stick. It is set by the HOME
> environmental
> variable.
>
> You will need to decide on a directory structure. For my tests, with the
> USB stick mounted as drive f:, I installed Python into f:\python3, and
> created a directory f:\user\python to use for both the user base and home
> directories. I set the environmental variables and run Python using the
> following cmd file named pyth.cmd:
>
> @echo off
> setlocal
> path f:\python3\Scripts;f:\python3;%PATH%
> set PYTHONUSERBASE=f:\user\python
> set HOME=f:\user\python
> call python %*
> endlocal
>
> After I installed Python 3.7 for the f:\python3 directory, I updated pip:
>
> pyth -m pip install --upgrade pip
>
> I have found that some python installers do not install wheel, and
> therefore some packages don't install because they can't build their
> wheels. So I now always run:
>
> pyth -m pip install --upgrade wheel
>
> This time, there was no previous wheel installation. Then I installed Leo:
>
> pyth -m pip install leo
>
> Running Leo, everything worked the first time:
>
> pyth -m leo.core.runLeo --use-docks
>
> I copied my standard settings from the myLeoSettings.leo file in my
> usual on-computer Leo installation. Note that I always run Leo with the -m
> leo.core.runLeo invocation because I find that sometimes I don't have a
> leo, runLeo, or launchLeo installed - depending on what Leo package I'm
> using - but this way always works. (Or maybe I do have them but my system
> path doesn't find them. Anyway, this method is very dependable.).
>
> I have run Leo on this usb stick on two different Windows 10 computers. I
> did have to edit the batch file paths from f:\ to e:\ because the mount
> name of the drive was different on the two computers. I haven't come up
> with a way to adapt to the change in drive letter except by editing the
> batch file, sorry to say.
>
> The stick did fail to work on a third computer. However, that one was so
> old that Windows hadn't been able to update itself for two or maybe even
> three years. So I expect there is some kind of DLL incompatibility going
> on. I would get the Leo splash screen but then it would die with no error
> message to the console. One of the computers that did work was a laptop I
> got back around 2012 (which has been able to be updated, though I'm
> retiring it so it may not get many more updates). So an old computer
> doesn't necessarily mean that this USB stick technique won't work.
>
> Of course, you could do all the usual maneuvers to use Leo from a git
> clone or a zip download if you want to.
>
> I hope this will be useful to someone.
>
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