How do I pass an equal sign when calling a batch script in Powershell?

We have a batch file that invokes our MSBuild-based build process. Syntax:

build App Target [ Additional MSBuild Arguments ]

Internally, it does this:

msbuild.exe %1.msbuild /t:%2 %3 %4 %5 %6 %7 %8 %9

Which results in calls to MSBuild that look like this:

msbuild.exe App.msbuild /t:Target

When any argument contains the equal sign, =, Powershell completely removes it. My batch script never sees it. This does not happen with the standard cmd.exe command prompt.

For example, if I call

build App Target "/p:Property=Value"

this is what gets passed to MSBuild:

msbuild.exe App.msmbuild /t:Target /p:Property Value

I expected this:

msbuild.exe App.msbuild /t:Target "/p:Property=Value"

I've tried the Powershell escape character, the standard Command Prompt escape character, and even stuff I made up:

build App Target "/p:Property=Value"
build App Target '/p:Property=Value'
build App Target /p:Property^=Value
build App Target /p:Property`=Value
build App Target /p:Property==Value

None of it works. What do I do to get the equal sign to not be stripped out or removed?


I've seen this before and have found a way to trick it out. I wish I could explain what's going on in particular with the '=' but I cannot. In your situation I'm fairly certain the following will work if you want to pass properties to msbuild:

build App Target '"/p:Property=Value"' 

When echoed, this produces the following:

msbuild.exe App.msbuild /t:Target "/p:Property=Value"

With PowerShell 3 you can use --% to stop the normal parsing powershell does.

build --% App Target "/p:Property=Value"

I don't know if there's an easier answer (I think not) but you can solve the problem by using .Net's process class to invoke cmd.exe. Here's an example:

# use .NET Process class to run a batch file, passing it an argument that contains an equals sign. 
# This test script assumes the existence of a batch file "c:\temp\test.bat"
# that has this content:
#      echo %1
#      pause
$cmdLine =  $cmdLine =  '/c c:\temp\test.bat "x=1"'
$procStartInfo =  new-object System.Diagnostics.ProcessStartInfo("cmd", $cmdLine )
$proc = new-object System.Diagnostics.Process
$proc.StartInfo = $procStartInfo

Have you tried single quotes to force a literal interpretation?

Or: cmd /c 'msbuild.exe App.msbuild /t:Target "/p:Property=Value"'

It seems that only single-quote around double-quote might be the best for multiple scenario around windows environment. Following link from MS shows its support(or limitation) of equal sign It is specific to Batch Files but it likely affect lots of other MS shell products.

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