Advanced Windows PowerShell Scripting Video Training

Advanced Windows PowerShell Scripting Video Training
Advanced Windows PowerShell Scripting Video Training

Friday, September 6, 2013

Odd Behavior When creating BAT Files with PowerShell

Just the fact the I’m using PowerShell to create BAT files is odd enough.  This pesky little problem cost me many hours of precious time.  Essentially, I’m writing some PowerShell code to look at some BAT files and then reconfigure them according to my scripts logic.  That all works flawlessly.  The problem is some extra bits added to the beginning of each line. I was using the Out-File cmdlet to save the new paths to the BAT file.  Take a look at this one line:

"Dir" | Out-FileLiteralPath "J:\PSTest.bat" 

 

Simple enough.  It created a BAT file call PSTest with only one command, “DIR”.  This is what happens when you run it.

image

What is the mysterious character in front of the “D”?  I tried to implement this in several different ways.  File redirection using “>>” did not work.  It yielded the same results.  I also tried the –encoding parameter of Out-File.  Same result. Using Get-Content in PowerShell, Type in DOS, or even opening the file in Notepad would produce a normal looking file.  No signs of the mysterious character. I finally settled on Add-Content.

Add-Content will add a line of text to a text file.  Since this file would be changing often, I had to include code that would test for the existence of the file and remove it if it was already there:

# See is a configuration file already exists.

# Make sure it is empty.

If (Test-Path -Path "J:\PSTest.bat")

{

    Remove-Item "J:\PSTest.bat"

}

 

Now I can add as many commands as I want by calling Add-Content.

Add-Content -Path "J:\PSTest.bat" -Value "DIR"

 

Now the mysterious character is no longer present and the batch file will execute normally.

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