PowerShell - Merge two variables into one

Question

I'm learning PowerShell so please forgive (what I'm sure is) a simple question.

I'm used to coding BATCH scripts and if I wanted to merge %USERDOMAIN% and %USERNAME% I would:

set zFullUsername=%USERDOMAIN%\%USERNAME%
echo %zFullUsername%

How can I do the same in PowerShell?

Thank you for your time.

Answer 1

In PowerShell, you can access environment variables in a few different ways. The way I recommend is to use the $env:VAR variable to access them.

$user = $env:USERNAME
$domain = $env:USERDOMAIN

echo "$domain\$user"

Note: \ is not an escape character in the PowerShell parser, ` is.

Similarly to rendering the echo command (echo is an alias of Write-Output btw) you can create a username variable like so:

$fullUserName = "$domain\$user"

Or you can skip right to creating $fullUserName straight from the environment variables:

$fullUserName = "${env:USERDOMAIN}\${env:USERNAME}"

Note: When variables have non-alphanumeric characters in them, the ${} sequence tells PowerShell everything between the ${} is part of the variable name to expand.

It seems the : in $env:VAR is actually an exception to this rule, as
"Username: $env:USERNAME" does render correctly. So the ${} sequence above is optional.

---

To avoid confusion when trying to apply this answer in other areas, if you needed to insert the value of an object property or some other expression within a string itself, you would use a sub-expression within the string instead, which is the $() sequence:

$someVar = "Name: $($someObject.Name)"

When using either ${} or $(), whitespace is not allowed to pad the outer {} or ().