================================================ Installing and Using Python Launcher for Windows

Binary Builds

You can get 32- and 64-bit binary installers from the Downloads section.

Source Builds

You should be able to clone this repository, then build the executables using Visual Studio (2022 Editions should work).

Once the executables have been built, you can run buildmsi.py to build the installers (you'll need the WiX Toolset v4 https://wixtoolset.org/docs/intro/#nettool installed and on your path in order to do this).

Installation and Uninstallation

You can install the launcher using

msiexec /i launcher.msi

for a 32-bit system. If all goes well, the launcher will be installed, and you should see a message box indicating that installation was successful.

Installing the launcher will change the file associations for Python files (ones with extensions of .py, .pyw, .pyc and .pyo). These will be handled by the installed launcher. If you previously had associations for these files, they should be restored when the launcher is uninstalled.

You can uninstall using

msiexec /x launcher.msi

On successful uninstallations, any file associations for Python files should be restored to what they were before you installed the launcher. If there were no previous file associations, the launcher will display a dialog showing all installed Pythons and offer you the option of associating Python files with one of them. You can choose to associate with a Python of your choice, or avoid associating these files altogether.

Variants of the launcher

There are four variants of the launcher MSI which you can download:

launcher.msi 32-bit launcher, installs to \Program Files\Python Launcher launcher.amd64.msi 64-bit launcher, installs to \Program Files\Python Launcher launchwin.msi 32-bit launcher, installs to \Windows launchwin.amd64.msi 64-bit launcher, installs to \Windows

One advantage of the versions which install to the Windows folder is that you can invoke the launcher itself more easily, using just "py" or "pyw", as the Windows folder is on the PATH for both 32-bit and 64-bit executables.

User Permissions

There are a couple of points worth noting about how the installers work:

1. If you don't have administrator rights on the machine you're installing on, you probably won't be able to complete the installation, because you don't have permissions to write to the "Program Files" folder.

2. By default, all installations run using MSIEXEC will attempt to perform an installation for the current user: this means registry changes will be made under HKEY_CURRENT_USER rather than HKEY_LOCAL_MACHINE. To install for all users, use a command line of the form

   msiexec /i launcher.msi ALLUSERS=1

   This will attempt an all-users installation, which will fail if you don't have administrator access. As an alternative, you can do

   msiexec /i launcher.msi ALLUSERS=2

   which will do an all-users installation (if you have administrator access) or a per-user installation (if you don't).

Usage

See the PEP for how the launcher is supposed to work. In practice, once the launcher is installed, you can run any Python script on your system even if Python is not on the path, simply invoking the script by name (if you have .py and .pyw in your PATHEXT environment variable, you don't even need to specify the extension):

C:\Users\Vinay> script arg1 arg2 arg3

If you have more than one Python installed, the first line of the script can indicate a specific Python to run it with:

#!python -> the default Python (usually the most recent Python 2.x) #!python2 -> the most recent Python 2.x #!python3 -> the most recent Python 3.x #!python3.2 -> Python 3.2 (an error will be raised if that's not installed)

Basic Documentation

Basic documentation in ReStructuredText format can be found at

https://github.com/oleksis/pylauncher/blob/master/docs/launcher.rst

Software Status

The software is currently in beta status - while it is reasonably stable, you may experience problems on installation or uninstallation. If for any reason you cannot uninstall the launcher using msiexec, you can use the msizap utility from Microsoft for this (it's part of the Windows SDK - free to download).

If you need to use msizap, these are the Windows Installer product codes for the launcher MSIs:

{298B5D62-1287-427F-B8D9-B44D605F8F6B} (32-bit) {1CB6C42B-5887-47CF-AF21-988256F0455B} (64-bit)

If you find any problems, please file a ticket in the Issues section.