Writes env vars matching a prefix to a file. E.g. `write-env-vars.ps1 -Prefix MYAPP_ -Path Environment.config` Useful if you want env vars from your build system to be available to your deployed app.

write-env-vars.ps1

param([String] $prefix, [String] $path)

# Write-Out environment variables to file.
Get-ChildItem env:* | Where-Object Name -Like "$($prefix)*" | ForEach-Object {
  $name = $_.Name.Replace("_", ".")
  $key = $name -Replace ":([\d]+):", "[`${1}]"
  Write-Output "$key=$($_.Value)"
} | Out-File -FilePath $path

Goes well with this: https://gist.github.com/jwatney/b7bdfd124f299d5e616716ec700951cf