如何从powershell运行基于python hashbang的python程序？

Question

我有几个python3脚本使用hashbang将其标识为python3脚本。这些脚本可以根据文件扩展名被标识为python，因为它们没有任何扩展名（就像在任何其他*nix系统中一样）。在

我已经讨论过相关的问题，但是它们没有解决这个特殊的需求，并且似乎依赖于*.py扩展来获得识别。在

• Set up Python on Windows to not type "python" in cmd
• How to make python scripts executable on Windows?

所以我的脚本名为：myscript，文件的第一行是：

#!/usr/bin/env python3
...

如何让Windowspowershell识别并使用位于^{的python解释器运行它？

---

更新-1

为了澄清，我想从powershellCLI运行它，而不是单击它。 另外，我刚刚发现（让我感到恐怖的是）当您将pip install与本机Windows Python3一起使用时，第一行hashbang会自动替换为：

#!c:\python37\python.exe

哎哟！在

---

更新-2

多亏了@eryksun的评论，我设法得到了一个PowerShell脚本来为我做一些基本的检查。但是，它需要被修复以支持比Python更多的内容。在

test4script.ps1：

^{pr2}$

结果是：

$ Get-Content -Path nonscript -TotalCount 3
#This aint right
echo "hello"

$ Get-Content -Path pip-describe -TotalCount 3
#!c:\python37\python.exe
# pip-describe - Show full text package description from PyPI
# -*- coding: utf-8 -*-

$ .\test4script.ps1 nonscript
File is not a known script. No shebang fund in file!

$ .\test4script.ps1 pip-describe
DEBUG: checking for common shebangs
DEBUG: found shebang for: python3

 Usage:  pip-describe <package-name>

 This will return the full-text package description (usually the README)
 as found on PyPI, for any given <package-name>.
 ...

现在我们应该能够使用命令行.exe使用：

cmd /c assoc .=unknown
cmd /c "ftype unknown=""C:\mybin\test4script.ps1"" %1"

但是，如果使用PowerShell独立地执行此操作，而不必跳过CMD，则会更好。在

Answer 1

eryksun提供了关于这个问题的很好的注释，基于它们的编辑显示了如何安装一个通用的、机器范围的shebang行感知启动器，用于通过将.添加到$env:PATHEXT来执行的无扩展脚本。在

这种方法需要注意的事项：

• PowerShell当前（从PowerShell Core 6.2.0开始）总是在新的控制台窗口中执行无扩展名的文件，这使得PowerShell中的此配置无效—不过，从cmd.exe开始，它确实按预期工作。在

  • PowerShell的行为应该被视为一个错误，并在this GitHub issue中报告。在

• 该机制存在潜在的安全风险，因为任何没有扩展名且带有shebang行的纯文本文件都会有效地变为可执行文件，从而可能会绕过针对具有已知可执行扩展名的文件的安全功能。

• 通过[PowerShell]脚本实现文件类型定义的默认操作总是需要使用脚本文件的解释器创建一个子进程，在本例中，这意味着使用其-File参数调用{}。powershell.exe的启动性能成本非常高，这会延迟执行。

• 如果您确实想实现这种通用机制，请参见底部的
  Install-ShebangSupport.ps1脚本。

---

鉴于上述情况，这里有一个更轻量级的Python特定方法，它基于自动为无扩展shebang行Python脚本创建单个*.ps1包装脚本：

这充分利用了PowerShell只允许按文件名执行自己的*.ps1脚本文件这一事实。在

限制：

• 您需要至少运行一次包装器脚本生成脚本（如下所示），每次添加新的无扩展的Python脚本时。

• 可以想象，可以使用一个文件系统观察程序来触发生成脚本，但是设置它是一项非常重要的工作。

好的一面是，包装器脚本比基于文件类型的通用解决方案执行得更快，因为不涉及额外的PowerShell实例（子进程）。在

从无扩展Python脚本所在的目录运行以下脚本^[1]：

Get-ChildItem -File | Where-Object Extension -eq ''  | % { 
  if ((Get-Content -LiteralPath $_.fullname -First 1) -match '^#!.*\bpython') {
    @'
py.exe ($PSCommandPath -replace '\.ps1$') $Args; exit $LASTEXITCODE
'@ > ($_.FullName + '.ps1')
  }
}

对于每个无扩展的Python脚本somescript，都会创建一个配套的somescript.ps1文件，该文件将somescript传递给Python启动器py.exe，以及任何命令行参数；exit $LASTEXTICODE确保{}的退出代码被传递。
正如eryksun所说，py.exe应该能够解释shebang行以调用适当的Python可执行文件。在

如果您不想让包装器文件扰乱系统，自动生成函数作为另一种选择，但请注意，您必须将它们加载到每个会话中才能使用，通常通过$PROFILE文件：

^{pr2}$

注意：

• 这将使当前目录的无扩展名Python脚本可用，就好像它们位于$env:PATH中列出的目录中一样，无论当前目录是否列在那里。

• 每个目标Python脚本都被硬编码到一个同名的函数中，并始终以该脚本为目标。在

  • 相比之下，*.ps1包装器脚本文件方法允许在给定目录中进行目标调用，类似于.\foo。在

• Invoke-Expression的这种特殊用法是安全的，可以根据可扩展字符串定义函数，但是^{} should generally be avoided。

---

脚本Install-ShebangSupport.ps1用于安装直接执行的通用支持基于Windows的无扩展shebang行脚本：

• 该脚本支持在当前用户级别（默认情况下或使用-Scope CurrentUser）或所有用户级别安装（使用-Scope AllUsers，需要以管理员身份运行）。

• 假设当前目录中存在，运行Get-Help .\Install-ShebangSupport以获得基本帮助。
  不带参数调用脚本将打印一个确认提示，其中包含对系统所需修改的详细信息；Ctrl-C可用于在不安装的情况下中止；传递-Force执行安装而不提示确认。

• 要稍后卸载，请传递-Uninstall；请注意，您必须匹配安装期间使用的（隐含的）-Scope值。

^{实现说明：通过cmd.exe-内部命令assoc和ftype定义无扩展名文件类型对所有用户都有效，因为这些定义存储在HKEY_LOCAL_MACHINE\Software\Classes的注册表中；而且，调用也总是需要提升（管理权限）。
但是，可以通过直接操作注册表来创建用户级定义，这也是该脚本用于计算机级定义的方法。}

^{注意：语法突出显示在下面的代码中被打断，但它确实起作用。}

<#
.SYNOPSIS
Support for direct execution of extension-less script files with shebang lines
on Windows.

.DESCRIPTION
For details, invoke this script without arguments: the confirmation prompt
will show the required modifications to your system. Submit "N" to opt out
of the installation.

Note that extension-less files that do not have a shebang line will open in 
the default text editor.

.PARAMETER Scope
Whether to install support for the current user only (the default) or
for all users (requires invocation as admin).

.PARAMETER Uninstall
Uninstalls previously installed support.
Note that the (implied) -Scope value must match the one that was used during
installation.

.PARAMETER Force
Bypasses the confirmation prompt that is shown by default.

.EXAMPLE
Install-ShebangSupport

Installation for the current user that requires answering a confirmation prompt.

.EXAMPLE
Install-ShebangSupport -Scope AllUsers -Force

Installation for all users without confirmation prompt. Requires invocation
as admin.

.EXAMPLE
Install-ShebangSupport -Uninstall

Uninstallation for the current user with confirmation prompt.
#>

[CmdletBinding(PositionalBinding=$false)]
param(
  [ValidateSet('CurrentUser', 'AllUsers')]
  [string] $Scope = 'CurrentUser'
  ,
  [switch] $Force
  ,
  [switch] $Uninstall
)

$ErrorActionPreference = 'Stop'; Set-StrictMode -Version 1
if ($env:OS -ne 'Windows_NT') { Throw ("This script can only run on Windows.")}

#             BEGIN: Internal helper functions

# === INSTALL
function install {

  Write-Verbose ('Installing shebang-script support for {0}:' -f ('the current user', 'ALL users')[$forAllUsers])

  # NOTE:
  #  * assoc and ftype only ever operate on HKEY_LOCAL_MACHINE\Software\Classes, not HKEY_CURRENT_USER\Software\Classes - both on reading and writing.
  #  * *HKEY_CURRENT_USER*-level definitions DO work, but *neither assoc nor ftype report them or can update them*.
  # Therefore, we perform direct registry manipulation below.

  Write-Verbose 'Creating file type for extension-less file names via the registry...'

  # Map the "extension-less extension", "." to the name of the new file type to be created below.
  # Caveat: Sadly, New-Item -Force blindly recreates the registry key if it already exists, discarding
  #         all existing content in the process.
  $key = New-Item -Force -Path $regkeyExtensionToFileType
  $null = New-ItemProperty -LiteralPath $key.PSPath  -Name '(default)' -Value $fileTypeName

  # Define the new file type:
  $key = New-Item -Force -Path "$regkeyFileType\Shell\Open\Command"
  $null = New-ItemProperty -LiteralPath $key.PSPath  -Name '(default)' -Value ('powershell.exe -noprofile -file "{0}" "%1" %*' -f $helperScriptFullName)

  # Get the current $env:PATHEXT definition from the registry.
  $currPathExt = [Environment]::GetEnvironmentVariable('PATHEXT', ('User', 'Machine')[$forAllUsers])
  if (-not $forAllUsers -and -not $currPathExt) {
    Write-Verbose "Creating a static user-level copy of the machine-level PATHEXT environment variable..."
    $currPathExt = [Environment]::GetEnvironmentVariable('PATHEXT', 'Machine')
  }

  # Add "." as an executable extension to $env:PATHEXT so as to support
  # direct execution of extension-less files.
  if ($currPathExt -split ';' -notcontains '.') {
    Write-Verbose "Appending '.' to PATHEXT..."
    [Environment]::SetEnvironmentVariable('PATHEXT', $currPathExt + ';.', ('User', 'Machine')[$forAllUsers])
    # Also define it for the running session
    $env:PATHEXT += ';.'
  } else {
    Write-Verbose "'.' is already contained in PATHEXT."
  }

  # The following here-string is the source code for the
  # $helperScriptFullName script to create.
  # To debug and/or modify it:
  #   * Edit and/or debug $helperScriptFullName
  #   * After applying fixes / enhancements, replace the here-string
  #     below with the updated source code.
  @'
  # When invoked by direct execution of a script file via the file-type definition, the arguments are:
  #  * The full path of the script file being invoked.
  #  * Arguments passed to the script file on invocation, if any.
  #    CAVEAT: PowerShell's own parsing of command-line arguments into $args
  #            breaks unquoted tokens such as >> -true:blue << and >> -true.blue << into *2* arguments
  #            ('-true:', 'blue' and '-true', '.blue', respectively).
  #            The only way to avoid that is to pass the argument *quoted*: '-true:blue' and '-true.blue'
  #            See https://github.com/PowerShell/PowerShell/issues/6360

  # Parse the arguments into the script
  param(
    [Parameter(Mandatory=$true)] [string] $LiteralPath,
    [Parameter(ValueFromRemainingArguments=$true)] [array] $passThruArgs
   )

  $ErrorActionPreference = 'Stop'; Set-StrictMode -Version 1

  # Note: When invoked via the file-type definition, $LiteralPath is guaranteed to be a full path.
  # To also support interactive use of this script (for debugging), we resolve the script 
  # argument to a full path.
  # Note that if you pass just a script filename (<script>), it'll be interpreted relative 
  # to the current directory rather than based on an $env:PATH search; to do the latter, 
  # pass (Get-Command <script>).Source
  if ($LiteralPath -notmatch '^(?:[a-z]:)?[\\/]') { $LiteralPath = Convert-Path -LiteralPath $LiteralPath }

  # Check the script's first line for a shebang.
  $shebangLine = ''
  switch -Regex -File $LiteralPath {
    '^#!\s*(.*)\s*$' { # Matches a shebang line.

      # Save the shebang line and its embedded command.
      $shebangLine = $_
      $cmdLine = $Matches[1]

      Write-Verbose "Shebang line found in '$LiteralPath': $shebangLine"

      break # We're done now that we have the shebang line.

    }

    default { # no shebang line found -> open with default text editor

      # Note: We cannot use Invoke-Item or Start-Process, as that would
      #       reinvoke this handler, resulting in an infinite loop.
      #       The best we can do is to open the file in the default text editor.

      Write-Verbose "No shebang line, opening with default text editor: $LiteralPath"

      # Obtain the command line for the default text editor directly from the registry
      # at HKEY_CLASSES_ROOT\txtfile\shell\Open\command rather than via `cmd /c ftype`,
      # because assoc and ftype only ever report on and update the *machine-level* definitions at 
      # HKEY_LOCAL_MACHINE\Software\Classes
      $cmdLine = [environment]::ExpandEnvironmentVariables((((Get-ItemProperty -EA Ignore registry::HKEY_CLASSES_ROOT\txtfile\shell\Open\command).'(default)') -split '=')[-1])
      if (-not $cmdLine) { $cmdLine = 'NOTEPAD.EXE %1' } # Fall back to Notepad.

      break # We're done now that we know this file doesn't have a shebang line.

    }

  }

  # Parse the shebang line's embedded command line or the default-text-editor's command line into arguments.
  # Note: We use Invoke-Expression and Write-Output so as to support *quoted*
  #       arguments as well - though presumably rare in practice.
  #       If supporting quoted tokens isn't necessary, the next line can be replaced 
  #       with a strictly-by-whitespace splitting command:
  #         $cmdArgs = -split $cmdLine
  [array] $cmdArgs = (Invoke-Expression "Write-Output   $($cmdLine -replace '\$', "`0")") -replace "`0", '$'

  if ($shebangLine) {

    # Extract the target executable name or path.
    # If the first argument is '/usr/bin/env', we skip it, as env (on Unix-like platforms) is merely used
    # to locate the true target executable in the Path.
    $exeTokenIndex = 0 + ($cmdArgs[0] -eq '/usr/bin/env')
    $exeNameOrPath = $cmdArgs[$exeTokenIndex]
    $exeFullPath = ''

    # Note: We do NOT pass any remaining arguments from the shebang line through.
    #       (Such arguments are rare anyway.)
    #       The rationale is that an interpreter that understands shebang lines will
    #       also respect such arguments when reading the file - this is true of at
    #       least py.exe, the Python launcher, and ruby.exe

    # Python is a special case: the Python launcher, py.exe, is itself
    # capable of interpreting shebang lines, so we defer to it.
    if ($exeNameOrPath -match '\bpython\d?') {
      # Ensure that 'py.exe' is available; if not, we fall back to the same approach 
      # as for all other executables.
      $exeFullPath = (Get-Command -CommandType Application py.exe -ErrorAction Ignore).Source
    }

    if (-not $exeFullPath) {
      # Try the executable spec. as-is first, should it actually contain a *Windows* path name.
      $exeFullPath = (Get-Command -CommandType Application $exeNameOrPath -ErrorAction Ignore).Source
      if (-not $exeFullPath) {
        # If not found, assume it is a Unix path that doesn't apply, and try to locate the hopefully
        # appropriate executable by its filename only, in the Path.
        $exeFullPath = (Get-Command -CommandType Application (Split-Path -Leaf -LiteralPath $exeNameOrPath) -ErrorAction Ignore).Source
      }
    }

    # Abort, if we can't find a suitable executable.
    if (-not $exeFullPath) { Throw "Could not find a suitable executable to run '$LiteralPath' based on its shebang line: $shebangLine" }

    # Synthesize the complete list of arguments to pass to the target exectuable.
    $passThruArgs = , $LiteralPath + $passThruArgs

  } else {  # NON-shebang-line files: invocation of default text editor

    $exeFullPath, [array] $editorArgs = $cmdArgs -replace '%1', ($LiteralPath -replace '\$', '$$')

    # Synthesize the complete list of arguments to pass to the target exectuable.
    # Replace the '%1' placeholder with the script's path.
    # Note that we don't really expect additional arguments to have been passed in this scenario,
    # and such arguments may be interpreted as additional file arguments by the editor.
    $passThruArgs = ($editorArgs -replace '"?%1"?', ($LiteralPath -replace '\$', '$$$$')) + $passThruArgs

    # If the editor is a GUI application, $LASTEXITCODE won't be set by PowerShell.
    # We set it to 0 here, as it has no value by default, and referencing it below with exit
    # would cause an error due to Set-StrictMode -Version 1.
    $LASTEXITCODE = 0
  }

  Write-Verbose "Executing: $exeFullPath $passThruArgs"

  # Invoke the target executable with all arguments.
  # Important:
  #  * We need to manually \-escape embeded " chars. in arguments
  #    because PowerShell, regrettably, doesn't do that automatically.
  #    However, even that may fail in edge cases in Windows PowerShell (fixed in PS Core), 
  #    namely when an unbalanced " char. is part of the first word - see https://stackoverflow.com/a/55604316/45375
  & $exeFullPath ($passThruArgs  -replace '"', '\"')

  # Pass the target executable's exit code through.
  # (In the case of invoking the default editor for non-shebang-line files, it 
  # won't have been set, if the editor is a GUI application.)
  exit $LASTEXITCODE
'@ |
    Set-Content -Encoding Utf8 -LiteralPath $helperScriptFullName

}

# === UNINSTALL
function uninstall {

  Write-Verbose ('Uninstalling shebang-script support for {0}:' -f ('the current user', 'ALL users')[$forAllUsers])

  Write-Verbose 'Removing file type information from the registry...'

  foreach ($regKey in $regkeyExtensionToFileType, $regkeyFileType) {
    if (Test-Path -LiteralPath $regKey) {
      Remove-Item -Force -Recurse -LiteralPath $regkey
    }
  }

  # Get the current $env:PATHEXT definition from the registry.
  $currPathExt = [Environment]::GetEnvironmentVariable('PATHEXT', ('User', 'Machine')[$forAllUsers])

  # Remove the "." entry from $env:PATHEXT
  $newPathExt = ($currPathExt -split ';' -ne '.') -join ';'
  if ($newPathExt -eq $currPathExt) {
    Write-Verbose "'.' is not contained in PATHEXT; nothing to do."
  } else {
    # For user-level uninstallations: as a courtesy, we compare the new PATHEXT value
    # to the machine-level one, and, if they're now the same, simply REMOVE the user-level definition.
    Write-Verbose "Removing '.' from PATHEXT..."
    if (-not $forAllUsers) {
      $machineLevelPathExt = [Environment]::GetEnvironmentVariable('PATHEXT', 'Machine')
      if ($newPathExt -eq $machineLevelPathExt) { $newPathExt = $null }
      Write-Verbose "User-level PATHEXT no longer needed, removing..."
    }
    [Environment]::SetEnvironmentVariable('PATHEXT', $newPathExt, ('User', 'Machine')[$forAllUsers])
    # Also update for the running session
    $env:PATHEXT = if ($newPathExt) { $newPathExt } else { $machineLevelPathExt }
  }

  Write-Verbose "Removing helper PowerShell script..."
  if (Test-Path -LiteralPath $helperScriptFullName) {
    Remove-Item -Force -LiteralPath $helperScriptFullName
  }

}

#             END: Internal helper functions

$forAllUsers = $Scope -eq 'AllUsers'
$verb = ('install', 'uninstall')[$Uninstall.IsPresent]
$operation = $verb + 'ation'

# If -Scope AllUsers was passed, ensure that the session is elevated.
$mustElevate = $forAllUsers -and -not ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole('BUILTIN\Administrators')
if ($mustElevate) {
  Throw "In order to $verb for ALL users, you must run this script WITH ELEVATED PRIVILEGES (Run As Administrator)."
}

#  - Define names, registry and file locations.
# The path of the generic shebang runner script that we'll create below.
$helperScriptFullName = Join-Path ($HOME, $env:ALLUSERSPROFILE)[$forAllUsers] 'Invoke-ShebangScript.ps1'

# The name of the file type to create for extension-less files.
$fileTypeName = 'ShebangScript'

# Registry keys that need to be modified.
# "." represents extension-less files
$regkeyExtensionToFileType = 'registry::{0}\SOFTWARE\Classes\.' -f ('HKEY_CURRENT_USER', 'HKEY_LOCAL_MACHINE')[$forAllUsers]
$regkeyFileType = 'registry::{0}\SOFTWARE\Classes\{1}' -f ('HKEY_CURRENT_USER', 'HKEY_LOCAL_MACHINE')[$forAllUsers], $fileTypeName
#  - 

# Prompt for confirmation, unless -Force was passsed.
if ($Uninstall) { # UNINSTALL

  if (-not $Force -and -not $PSCmdlet.ShouldContinue(@"

You are about to UNINSTALL support for direct execution of extension-less
script files that have shebang lines.

Uninstallation will be performed for $(("the CURRENT USER only`n(invoke as admin with -Scope AllUsers to change that)", 'ALL USERS')[$forAllUsers]).

IMPORTANT: Uninstallation will only be effective if it is performed in the same
           (implied) -Scope as the original installation.

The following modifications to your system will be performed:

  * "." will be persistently REMOVED from your `$env:PATHEXT variable.

  * The following registry keys will be REMOVED:

      $($regkeyExtensionToFileType -replace '^registry::')
      $($regkeyFileType -replace '^registry::')

  * The following helper PowerShell script will be REMOVED:

    $helperScriptFullName 

Press ENTER to proceed, or Ctrl-C to abort.
"@, "Shebang-Script Direct-Execution Support - Uninstallation")) { # , $true, [ref] $null, [ref] $null)) {
    exit 1
  }

  # Call the uninstallation helper function
  uninstall

} else {  # INSTALL

  if (-not $Force -and -not $PSCmdlet.ShouldContinue(@"

You are about to install support for direct execution of Unix-style scripts 
that do not have a filename extension and instead define the interpreter to run
them with via shebangline ("#!/path/to/interpreter").

Support will be installed for $(("the CURRENT USER only`n(invoke as admin with -Scope AllUsers to change that)", 'ALL USERS')[$forAllUsers]).

Once installed, you will be able to run such scripts by direct invocation,
via a helper PowerShell script that analyzes the shebang line and calls the
appropriate interpreter.

CAVEATS:

  * ENABLING THIS INVOCATION MECHANISM IS A SECURITY RISK, because any
    plain-text file without an extension that has a shebang line
    effectively becomes executable, potentially bypassing security features
    that focus on files that have extensions known to be executable.

  * AS OF POWERSHELL CORE 6.2.0, direct execution of such extension-less files
    from PowerShell INVARIABLY RUNS IN A NEW CONSOLE WINDOW, WHICH MAKES USE
    FROM POWERSHELL VIRTUALLY USELESS.
    However, this is a BUG that should be fixed; see:
      https://github.com/PowerShell/PowerShell/issues/7769

The following modifications to your system will be performed:

  * "." will be added persistently to your `$env:PATHEXT variable, to enable
    direct execution of filenames without extension.

    NOTE: If you install with -Scope CurrentUser (the default), a static 
    user-level copy of the machine-level PATHEXT environment variable is 
    created, unless already present.

  * The following registry locations will be created or replaced to define a
    new file type for extension-less filenames:

      $($regkeyExtensionToFileType -replace '^registry::')
      $($regkeyFileType -replace '^registry::')

  * The helper PowerShell script will be created in:

    $helperScriptFullName 

NOTE: Any existing registry definitions or helper script will be REPLACED.

Press ENTER to proceed, or CTRL-C to abort.
"@, "Shebang-Script Direct-Execution Support - Installation")) {
    # !! The prompt defaults to *Yes* (!)
    # !! Sadly, if we wanted the prompt to be default to *No*, we'de be forced 
    # !! to also present pointless 'Yes/No to *All*' prompts, which would be confusing.
    # !! See https://github.com/PowerShell/PowerShell/issues/9428
    exit 1
  }

  # Call the installation helper function
  install
}

Write-Verbose "Shebang-support ${operation} completed."

if (-not $Force) {
  Write-Host "Shebang-support ${operation} completed."
}

exit 0

---

^{[1]在Windows PowerShell中，您可以使用Get-ChildItem -File -Filter *.来更方便、更高效地查找无扩展名的文件，但从v6.2.0开始，PowerShellCore中该功能已被破坏-请参见this GitHub issue。}