From time to time everyone faces this. You need templates - either HTML, email or just a couple of strings, but anyway… Here I’ve selected several solutions that may help you. If you know any other good solutions, feel free to mention them in comments - I’ll add them to this post.

ExpandString - fast and dirty

Original post by NerdyMishka

$Name = "Dude"
$ExecutionContext.InvokeCommand.ExpandString('Hello ${Name}!!!');

You can use PowerShell execution context on a string to replace variables with their values. It wil actually pass the string through PowerShell interpreter, so you can use any PowerShell syntax inside. The main problems are:

• You must prevent arbitraty code execution, because ExecutionContext supports $(...)
• Context has access to all variables within execution scope. So the better way is to prepare the variables and call the context in a separate function.

String.Replace and Mustache templates

Yes, just replace in a string. Look at the code, it’s really simple:

function Merge-Tokens($template, $tokens)
{
    return [regex]::Replace(
        $template,
        '\$\{(?<tokenName>\w+)\}\$',
        {
            param($match)

            $tokenName = $match.Groups['tokenName'].Value

            return $tokens[$tokenName]
        })
}

There are lots of implementations: PSTokens and lots of GitHub gists.

Mustache

There’s a very good and straightforward standard called [mustache]{https://mustache.github.io/} that covers around 90% of all “templater” needs. Though it’s not officially mentioned, there are some PowerShell implementations, particularly Postache (based on .NET implementation) and BladePS - not really full implementation, but still works. I’d personally recommend Postache.

EPS - ERB-like templates

So, here’s the monster - EPS. It’s based on Ruby ERB templates ideas and internally executes PowerShell code in templates. Just read the Readme - it will explain things better than me.

PSStringTemplate

This engine’s implements StringTemplate4 - Java template engine with ports to several other languages. The templater docs can be found here

What to choose

For me, EPS and Mustache are the choices. In simple cases and to make the templates compact, I’ll use Mustache. But to feel all the power - EPS is the best for me.