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Pipe into executable through .lnk file

Time:06-02

I have an executable at C:\Very\Long\Path\StreamToClipboard.exe
The file C:\InPath\StreamToClipboard.lnk points to that executable.
The directory C:\InPath is in my PATH variable, and .lnk is in my PATHEXT variable.

In regular cmd, I can execute any of these commands:
echo Hello | C:\Very\Long\Path\StreamToClipboard.exe
echo Hello | C:\InPath\StreamToClipboard.lnk
echo Hello | StreamToClipboard.lnk
echo Hello | StreamToClipboard
and the the executable is started, the text "Hello" is correctly piped into that process.

In PowerShell, I can execute echo Hello | C:\Very\Long\Path\StreamToClipboard.exe and it works too. But all of the other commands don't work:

Fehler beim Ausführen des Programms "StreamToClipboard.lnk": Die angegebene ausführbare Datei ist keine gültige
Anwendung für diese Betriebssystemplattform.In Zeile:1 Zeichen:12
  echo foo | C:\InPath\StreamToClipboard.lnk
             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.
In Zeile:1 Zeichen:1
  echo foo | C:\InPath\StreamToClipboard.lnk
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      CategoryInfo          : ResourceUnavailable: (:) [], ApplicationFailedException
      FullyQualifiedErrorId : NativeCommandFailed

(and respective paths)
Which roughly translates to Error while executing "StreamToClipboard.lnk": The specified executable file is not a valid application for this operating system plattform.

Note that echo Hello | "C:\Very\Long\Path\StreamToClipboard.exe" also does not work, with a different error message:

In Zeile:1 Zeichen:14
  ... cho Hello | "C:\Very\Long\Path\StreamToClipboard.exe"
                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Ausdrücke sind nur als erstes Element einer Pipeline zulässig.
      CategoryInfo          : ParserError: (:) [], ParentContainsErrorRecordException
      FullyQualifiedErrorId : ExpressionsMustBeFirstInPipeline

Roughly translates to Expressions are only valid as the first element in a pipeline.

If I, instead of creating the .lnk file, copy the entire executable to C:\InPath\StreamToClipboard.exe, then these commands:
echo Hello | C:\InPath\StreamToClipboard.exe
echo Hello | StreamToClipboard.exe
echo Hello | StreamToClipboard
work fine.

How can I get PowerShell to accept echo Hello | StreamToClipboard (where it's an .lnk file), or at least echo Hello | StreamToClipboard.lnk?

CodePudding user response:

  • Unlike cmd.exe, PowerShell does not support invoking shortcut files (.lnk) like console applications; instead:
    • A new console window opens, asynchronously.

    • The process in the new console window does NOT receive stdin input (via the pipeline):

      • If a command is used - such as echo hello, using the built-in echo alias for PowerShell's (rarely needed) Write-Output cmdlet - the following error occurs, as of Windows PowerShell v5.1 / PowerShell (Core) 7.2.4:

        • Cannot run a document in the middle of a pipeline
      • If an expression - such as 'hello' - is used, no error occurs, but the input is effectively ignored.

    • In other words: PowerShell considers .lnk files documents, not executables, and defers to Windows (GUI) shell for opening them;[1] in effect, invoking a .lnk file is like passing it to Invoke-Item or Start-Process; adding -Wait to the latter makes the invocation synchronous, but still runs in a separate window and doesn't support stdin input; attempting to use -NoNewWindow and/or
      -RedirectStandardInput (to provide stdin input via a file) results in an error, similar to the one you saw:[2]

      • This command cannot be run due to the error: %1 is not a valid Win32 application.

Workarounds:

  • Call the target .exe file directly in your pipeline, which - if your path is quoted and/or contains variable references or expressions - requires use of &, the call operator:
# & is required, because the executable path is quoted.
# Note: 'Hello' is the PowerShell-idiomatic equivalent of
#        echo Hello
'Hello' | & "C:\Very\Long\Path\StreamToClipboard.exe"

Note: For simplicity, you may choose to always use & when invoking external programs, but it is only required in the cases mentioned above, discussed in more detail in this answer.

  • Invoke the shortcut (.lnk) file via cmd /c:
'Hello' | cmd /c C:\InPath\StreamToClipboard.lnk

Note that, in both workarounds, character encoding issues may arise, given that data is being sent to an external program:

  • The $OutputEncoding preference variable controls what encoding is used to send data to an external program.

  • The encoding stored in [Console]::OutputEncoding determines how PowerShell decodes data received from external programs.

  • See this answer for more information.


[1] Note that (temporarily) appending ";.LNK" to the value of $env:PATHEXT, the environment variable that lists all filename extensions that belong to executables, does not help.

[2] The reason is that these parameters cause Start-Process to switch from the ShellExecute WinAPI function to CreateProcess, and the latter only works with actual executables.

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