Powershell: pipe input to command executed via call operator


Powershell: pipe input to command executed via call operator

I need to execute a batch file dynamically via the call operator (&). The batch file takes arguments, but I also need to pass in some input on stdin. I thought this would work:
$command = “somebatchfile.bat”
“y” | & $command arg1 arg2

However, the “y” is not passed through in stdin. If I execute the batch file like this:
“y” | somebatchfile.bat arg1 arg2

Then everything works as expected. But I cannot hard-code the path.
How can I execute a dynamically-determined batch file that takes arguments and pass through some standard input as well?
In an effort to reproduce this, I did the following:
@echo off
call script2.bat %*

@echo off
set /p x=”Enter: ”
echo foo %* %x%

Powershell session:
> $command = “./script.bat”
> “yes!” | & $command whatever
Enter: foo whatever yes!

So it works as expected here. However, when I use it with the actual batch file (android.bat, part of the Android SDK), the input is not passed through to java.exe.
Here is the contents of android.bat:
n@echo off
rem Copyright (C) 2007 The Android Open Source Project
rem Licensed under the Apache License, Version 2.0 (the “License”);
rem you may not use this file except in compliance with the License.
rem You may obtain a copy of the License at
rem http://www.apache.org/licenses/LICENSE-2.0
rem Unless required by applicable law or agreed to in writing, software
rem distributed under the License is distributed on an “AS IS” BASIS,
rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rem See the License for the specific language governing permissions and
rem limitations under the License.

rem Useful links:
rem Command-line reference:
rem http://technet.microsoft.com/en-us/library/bb490890.aspx

rem don’t modify the caller’s environment
setlocal enableextensions

rem Set up prog to be the path of this script, including following symlinks,
rem and set up progdir to be the fully-qualified pathname of its directory.
set prog=%~f0

rem Grab current directory before we change it
set work_dir=%cd%

rem Change current directory and drive to where the script is, to avoid
rem issues with directories containing whitespaces.
cd /d %~dp0

rem Check we have a valid Java.exe in the path.
set java_exe=
call lib\find_java.bat
if not defined java_exe goto :EOF

set jar_path=lib\sdkmanager.jar;lib\swtmenubar.jar

rem Set SWT.Jar path based on current architecture (x86 or x86_64)
for /f “delims=” %%a in (‘”%java_exe%” -jar lib\archquery.jar’) do set swt_path=lib\%%a

rem Copy android.bat and its required libs to a temp dir.
rem This avoids locking the tool dir in case the user is trying to update it.

set tmp_dir=%TEMP%\temp-android-tool
xcopy “%swt_path%” “%tmp_dir%\%swt_path%” /I /E /C /G /R /Y /Q > nul
copy /B /D /Y lib\common.jar “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\commons-codec* “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\commons-compress* “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\commons-logging* “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\dvlib.jar “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\gson* “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\guava* “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\httpclient* “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\httpcore* “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\httpmime* “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\layoutlib-api.jar “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\org-eclipse-* “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\sdk* “%tmp_dir%\lib\” > nul
copy /B /D /Y lib\swtmenubar.jar “%tmp_dir%\lib\” > nul

rem jar_path and swt_path are relative to PWD so we don’t need to adjust them, just change dirs.
set tools_dir=%cd%
cd /d “%tmp_dir%”


rem The global ANDROID_SWT always override the SWT.Jar path
if defined ANDROID_SWT set swt_path=%ANDROID_SWT%

if exist “%swt_path%” goto SetPath
echo ERROR: SWT folder ‘%swt_path%’ does not exist.
echo Please set ANDROID_SWT to point to the folder containing swt.jar for your platform.
goto :EOF

rem Finally exec the java program and end here.
REM set REMOTE_DEBUG=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
call “%java_exe% %REMOTE_DEBUG%” “-Dcom.android.sdkmanager.toolsdir=%tools_dir%” “-Dcom.android.sdkmanager.workdir=%work_dir%” -classpath “%jar_path%;%swt_path%\swt.jar” com.android.sdkmanager.Main %*

rem EOF

The execution of the java app is prompting for license acceptance, which is why I want to pipe “y” into it. If I pipe directly it works, but if I pipe via Powershell’s call operator it does not.
This works:
“y” | android.bat update sdk -u -a -t 38

This does not:
$command = “android.bat”
“y” | & $command update sdk -u -a -t 38

Can anyone enlighten me?


Solution 1:

I believe that using & to invoke an executable requires that the parameters are a String Array rather than just a String. I think PowerShell is getting confused on how to handle that input. So, per your example, something like this should pass inputs and arguments correctly:

$command = ".\script1.bat"
$x = "update sdk|-u|-a|-t 38"
"myinput" | & $command $x.Split("|")

results in the output

Enter: foo "update sdk" -u -a "-t 38" myinput