I need to Execute a command-line command inside my PowerShell script, but also to use a store variable from Powershell Inside that command

Question

I'm kind of new to Powershell, but now I need to build a script which takes a backup and encrypts it using Veracrypt. Fortunately there is a command-line syntax to do that, but for my script I'll use the Powershell's shell instead. I've managed to call CMD from within my Powershell script, but then I need to user a pre-configured variable along with the command-line command, which I previously set in Powershell. To make a sense for my request, here's how my script goes:

$Folder="e:\shares\Test"

$Size=(Get-ChildItem $Folder -Recurse | Measure-Object -Sum Length).Sum

& 'C:\Program Files\VeraCrypt\VeraCrypt Format.exe' /create e:\shares\Test\test.hc /password test /hash sha512 /encryption serpent /filesystem NTFS /size $Size

As you can see from above example, I need to make the Veracrypt command make use of the $Size variable for the /size flag. That's because I assume that my backup size will change due time.

Is therea way to call my Powershell variable from CMD?

The Veracrypt command fails because it can't read the size input for the volume creation. That's where I needed to use my variable to set the size. But seems like cmd doesn't recognize it. — Shachar, Feb 19 '18 at 10:28
So if you hard-code a value instead of using your `$Size` variable; what happens? — gvee, Feb 19 '18 at 10:50
Then the command is successful. But that miss the entire purpose of my script. My backup size will differ from one backup process to another... — Shachar, Feb 19 '18 at 11:21
just trying to help you debug the solution `;-)` Does the value of `$Size` match the value you hard-coded? — gvee, Feb 19 '18 at 11:33
Yes. But the thing is that its not recognized as a variable. Thats all my issue is...thanks for the help so far :) — Shachar, Feb 19 '18 at 12:39
to be clear: `/size 10240` works, but `$Size=10240 ... /size $Size` does not?! — gvee, Feb 19 '18 at 14:11
Correct! :) As I said the variable is not recognized by the cmd.exe interprator. — Shachar, Feb 19 '18 at 14:24
Now that is maddeningly bizarre! Unfortunately that stumps me at the moment and, without an environment in which I can test your scenario, I don't think I can be of any more assistance. Sorry! — gvee, Feb 19 '18 at 15:08
In your code snippet, `cmd.exe` is _not_ involved: you're simply invoking a _console application_ directly from PowerShell, and passing arguments to it. There are many pitfalls associated with passing arguments to console applications, but the code in your question _should_ work, so there must be something you're not mentioning in your question. — mklement0, Feb 20 '18 at 02:29
Thanks for the help. This was resolved after changing the source folder! sorry for all the bothering! — Shachar, Feb 20 '18 at 07:37
@Shachar: Glad to hear it. I encourage you to _delete_ this question, then, given that it's unlikely to benefit future readers. — mklement0, Feb 21 '18 at 02:07

I need to Execute a command-line command inside my PowerShell script, but also to use a store variable from Powershell Inside that command

0 Answers0