Executing Powershell script from command line with quoted parameters - powershell

Question

I am automating the build of a legacy MS Access application, and in one of the steps, I am trying to make an Access executable (.ADE). I have come up with the following code, which is stored in a file (PSLibrary.ps1):
Add-Type -AssemblyName Microsoft.Office.Interop.Access
function Access-Compile {
param (
[Parameter(Mandatory=$TRUE,Position=1)][string]$source,
[Parameter(Mandatory=$TRUE,Position=2)][string]$destination
)
Write-Output "Starting MS Access"
$access = New-Object -ComObject Access.Application
$access.Visible = $FALSE
$access.AutomationSecurity = 1
if (!(Test-Path $source)) { Throw "Source '$source' not found" }
if ((Test-Path $destination)) {
Write-Output "File '$destination' already exists - deleting..."
Remove-Item $destination
}
Write-Output "Compiling '$source' to '$destination'"
$result = $access.SysCmd(603, $source, $destination)
$result
Write-Output "Exiting MS Access"
$access.quit()
}
If I go into the PowerShell ISE and run the command below, then everything works fine, and the expected output is created:
PS C:>& "C:\Temp\PSLibrary.ps1"
PS C:>Access-Compile "C:\Working\Project.adp" "C:\Working\Project.ade"
However, I can't seem to generate the right hocus-pocus to get this running from the command line, as I would in an automated build. For instance,
powershell.exe -command "& \"C:\\Temp\\PSLibrary.ps1\" Access-Compile \"C:\\Temp\\Project.adp\" \"C:\\Temp\\Project.ade\""
What am I doing wrong?

Answer 1

For complex parameters, you can use Powershell's -EncodedCommand parameter. It will accept a Base64 encoded string. No escaping is needed for quotes, slashes and such.
Consider a test function that will print its parameters. Like so,
function Test-Function {
param (
[Parameter(Mandatory=$TRUE,Position=1)][string]$source,
[Parameter(Mandatory=$TRUE,Position=2)][string]$destination
)
write-host "src: $source"
write-host "dst: $destination"
}
Create command to load the script and some parameters. Like so,
# Load the script and call function with some parameters
. C:\Temp\Calling-Test.ps1; Test-Function "some\special:characters?" "`"c:\my path\with\spaces within.ext`""
After the command syntax is OK, encode it into Base64 form. Like so,
[System.Convert]::ToBase64String([System.Text.Encoding]::UNICODE.GetBytes('. C:\Temp\Calling-Test.ps1; Test-Function "some\special:characters?" "`"c:\my path\with\spaces within.ext`""'))
You'll get a Base64 string. Like so,
LgAgAEMAOgBcAFQAZQBtAHAAXABDAGEAbABsAGkAbgBnAC0AVABlAHMAdAAuAHAAcwAxADsAIAAgAFQAZQBzAHQALQBGAHUAbgBjAHQAaQBvAG4AIAAiAHMAbwBtAGUAXABzAHAAZQBjAGkAYQBsADoAYwBoAGEAcgBhAGMAdABlAHIAcwA/ACIAIAAiAGAAIgBjADoAXABtAHkAIABwAGEAdABoAFwAdwBpAHQAaABcAHMAcABhAGMAZQBzACAAdwBpAHQAaABpAG4ALgBlAHgAdABgACIAIgA=
Finally, start Powershell and pass the encoded string as a parameter. Like so,
# The parameter string here is abreviated for readability purposes.
# Don't do this in production
C:\>powershell -encodedcommand LgAgA...
Output
src: some\special:characters?
dst: "c:\my path\with\spaces within.ext"
Should you later want to reverse the Base64 encoding, pass it into decoding method. Like so,
$str = " LgAgA..."
[Text.Encoding]::Unicode.GetString([System.Convert]::FromBase64String($str))
# Output
. C:\Temp\Calling-Test.ps1; Test-Function "some\special:characters?" "`"c:\my path\with\spaces within.ext`""

Answer 2

PowerShell like Bash can take single or double quotes
PS C:\Users\Steven> echo "hello"
hello
PS C:\Users\Steven> echo 'hello'
hello
this can alleviate some of the headache, also I think you can use the literal backslashes without escaping.
To run PowerShell, choose
Start Menu Programs Accessories
Windows Powershell Windows Powershell