Run dotnet new after install to prime cache for deb

Copy postinst to correct directory

Can only rely on env for get dotnet command

Print telemetry notice anyway

build/package/Installer.DEB.proj

@@ -41,6 +41,14 @@
         SkipUnchangedFiles="False"
         UseHardlinksIfPossible="False" />
 
+      <!-- Create layout: postinst -->
+      <Copy
+        DestinationFiles= "$(DebianPostinstFile)"
+        SourceFiles="$(DebianPostinstTemplateFile)"
+        OverwriteReadOnlyFiles="True"
+        SkipUnchangedFiles="False"
+        UseHardlinksIfPossible="False" />
+
       <!-- Create layout: Generate and Place debian_config.json -->
       <ReplaceFileContents
         InputFile="$(DebianConfigTemplateFile)"

build/package/Installer.DEB.targets

@@ -75,6 +75,11 @@
       <DebianConfigJsonFile>$(LayoutDirectory)/debian_config.json</DebianConfigJsonFile>
     </PropertyGroup>
 
+    <PropertyGroup>
+      <DebianPostinstTemplateFile>$(RepoRoot)/packaging/deb/postinst</DebianPostinstTemplateFile>
+      <DebianPostinstFile>$(LayoutDirectory)/debian/postinst</DebianPostinstFile>
+    </PropertyGroup>
+
     <ItemGroup>
       <DebianConfigTokenValues Include="%SHARED_FRAMEWORK_DEBIAN_PACKAGE_NAME%">
         <ReplacementString>$(SharedFxDebianPackageName)</ReplacementString>

packaging/deb/postinst

@@ -1,3 +1,15 @@
 #!/usr/bin/env sh
 echo "This software may collect information about you and your use of the software, and send that to Microsoft."
 echo "Please visit http://aka.ms/dotnet-cli-eula for more information."
+
+# Run 'dotnet new' to trigger the first time experience to initialize the cache
+echo "Welcome to .NET Core!
+---------------------
+Learn more about .NET Core @ https://aka.ms/dotnet-docs. Use dotnet --help to see available commands or go to https://aka.ms/dotnet-cli-docs.
+
+Telemetry
+--------------
+The .NET Core tools collect usage data in order to improve your experience. The data is anonymous and does not include command-line arguments. The data is collected by Microsoft and shared with the community.
+You can opt out of telemetry by setting a DOTNET_CLI_TELEMETRY_OPTOUT environment variable to 1 using your favorite shell.
+You can read more about .NET Core tools telemetry @ https://aka.ms/dotnet-cli-telemetry."
+dotnet new > /dev/null 2>&1 || true