Is there a way to determine the .NET Framework version from the command line?

To troubleshoot an installation, sometimes I just want a quick answer to what version of .NET is installed.

Is there a way to determine the .NET Framework version on a standard Windows system, other than looking at the directories?

NOTE: This is not for a development machine, just out-of-the-box windows

The following works, but I'm looking for a simpler way.

dir %WINDIR%\Microsoft.Net\Framework\v*

Directory of C:\Windows\Microsoft.Net\Framework

07/13/2009  07:20 PM    <DIR>          v1.0.3705
07/13/2009  07:20开发者_开发问答 PM    <DIR>          v1.1.4322
01/20/2010  01:16 PM    <DIR>          v2.0.50727
07/13/2009  09:37 PM    <DIR>          v3.0
01/20/2010  01:02 PM    <DIR>          v3.5
02/10/2010  03:20 AM    <DIR>          v4.0.21006

UPDATE: Not a solution, but another cool directory formatted listing

dir %WINDIR%\Microsoft.Net\Framework\v* /O:-N /B

v4.0.21006
v3.5
v3.0
v2.0.50727
v1.1.4322
v1.0.3705

reg query "HKLM\Software\Microsoft\NET Framework Setup\NDP" /s /v version | findstr /i version | sort /+26 /r

The top entry is the latest version of the framework installed.

Note: This doesn't work with v1.x of the framework.

Update: I missed the comment that you are looking for something to tell your dad over the phone. If that's the case, the command above is probably not the best approach for you. You might be better off just telling your dad to open Windows Explorer and navigate him to the .NET Framework dir and telling you the numbers in there.

Based on your update which indicates this is for walking a non-tech savvy end user through it, I suggest going to Scott Hanselman's site http://www.smallestdotnet.com (use Internet Explorer) which uses the user agent string to tell you which .NET Framework you've got and gives you recommendations for getting up to the latest version in the most efficient manner.

Old Answer
With PowerShell you could do this (although the presence of PowerShell already implies at least .NET 2.0)

Get-ChildItem "$($Env:WinDir)\Microsoft.Net\Framework" -i mscorlib.dll -r |
    ForEach-Object { $_.VersionInfo.ProductVersion }

I don't know if there's a comparable way to get the version information in plain old crusty cmd.exe.

just open the VS2008 command prompt and type clrver

EDIT: my answer is irrelevant for the OP question (which was edited after I originally answered).

According to MSDN you can use the registry as well to check for installed versions.

In addition this site claims that there is a command line application called csc you can use - haven't tried it though, I use the registry way during installations I run.

The following would detect if .net framework 3.5 is installed or not.. and if not installed will install it. Just run this on the command prompt.

if exist "%WINDIR%\Microsoft.Net\Framework\v3.5" goto end start /wait .\Framework\dotnetfx.exe /q /norestart" :end 

If you want to detect other versions just replace v3.5 with v2.0 or v1.0 as the case may be. Further if .net is not detected the installation of the .net framework would be done in silent mode i.e. no ui or user interaction.

There is an article posted on CodeProject that can do just exactly that plus its command line based.

Hope this helps.

The highest version number from that directory listing is the installed version.

As you can see, any version includes all previous versions, so check for support of a specific version = check for that specific directory.