How to run a PowerShell script within a Windows batch file

Question

How do I have a PowerShell script embedded within the same file as a Windows batch script?

I know this kind of thing is possible in other scenarios:

• Em

Answer 1

^{Also consider this "polyglot" wrapper script, which supports embedded PowerShell and/or VBScript/JScript code; it was adapted from this ingenious original, which the author himself, flabdablet, had posted in 2013, but it languished due to being a link-only answer, which was deleted in 2015.}

A solution that improves on Kyle's excellent answer:

<# ::
@setlocal & copy "%~f0" "%TEMP%\%~0n.ps1" >NUL && powershell -NoProfile -ExecutionPolicy Bypass -File "%TEMP%\%~0n.ps1" %*
@set "ec=%ERRORLEVEL%" & del "%TEMP%\%~0n.ps1"
@exit /b %ec%
#>

# Paste arbitrary PowerShell code here.
# In this example, all arguments are echoed.
'Args:'
$Args | % { 'arg #{0}: [{1}]' -f ++$i, $_ }

Note: A temporary *.ps1 file that is cleaned up afterwards is created in the %TEMP% folder; doing so greatly simplifies passing arguments through (reasonably) robustly, simply by using %*

• Line <# :: is a hybrid line that PowerShell sees as the start of a comment block, but cmd.exe ignores, a technique borrowed from npocmaka's answer.

• The batch-file commands that start with @ are therefore ignored by PowerShell, but executed by cmd.exe; since the last @-prefixed line ends with exit /b, which exits the batch file right there, cmd.exe ignores the rest of the file, which is therefore free to contain non-batch-file code, i.e., PowerShell code.

• The #> line ends the PowerShell comment block that encloses the batch-file code.

• Because the file as a whole is therefore a valid PowerShell file, no findstr trickery is needed to extract the PowerShell code; however, because PowerShell only executes scripts that have filename extension .ps1, a (temporary) copy of the batch file must be created; %TEMP%\%~0n.ps1 creates the temporary copy in the %TEMP% folder named for the batch file (%~0n), but with extension .ps1 instead; the temporarily file is automatically removed on completion.

• Note that 3 separate lines of cmd.exe statements are needed in order to pass the PowerShell command's exit code through.
  (Using setlocal enabledelayedexpansion hypothetically allows doing it as a single line, but that can result in unwanted interpretation of ! chars. in arguments.)

---

To demonstrate the robustness of the argument passing:

Assuming the code above has been saved as sample.cmd, invoking it as:

sample.cmd "val. w/ spaces & special chars. (\|<>'), on %OS%" 666 "Lisa \"Left Eye\" Lopez"

yields something like the following:

Args:
arg #1: [val. w/ spaces & special chars. (\|<>'), on Windows_NT]
arg #2: [666]
arg #3: [Lisa "Left Eye" Lopez]

Note how embedded " chars. were passed as \".
However, there are edge cases related to embedded " chars.:

:: # BREAKS, due to the `&` inside \"...\"
sample.cmd "A \"rock & roll\" life style"

:: # Doesn't break, but DOESN'T PRESERVE ARGUMENT BOUNDARIES.
sample.cmd "A \""rock & roll\"" life style"

These difficulties are owed to cmd.exe's flawed argument parsing, and ultimately it is pointless to try to hide these flaws, as flabdablet points out in his excellent answer.

As he explains, escaping the following cmd.exe metacharacters with ^^^ (sic) inside the \"...\" sequence solves the problem:

& | < >

Using the example above:

:: # OK: cmd.exe metachars. inside \"...\" are ^^^-escaped.
sample.cmd "A \"rock ^^^& roll\" life style"