psake task for getting assembly version for TeamCity

task GetBuildNumber { 
  $version = gc $base_directory\$solution_name\Properties\AssemblyInfo.cs | select-string -pattern "AssemblyVersion"
  $version -match '^\[assembly: AssemblyVersion\(\"(?<major>[0-9]+)\.(?<minor>[0-9]+)\.(?<revision>[0-9]+)\.(?<build>[0-9]+)\"\)\]' | Out-Null
  "##teamcity[buildNumber '{0}.{1}.{2}.{3}']" -f $matches["major"],$matches["minor"],$matches["revision"],$matches["build"]
}