vimalsdesk

Console tricks using Console class in PowerShell

Vimal Shekar — Sun, 18 Mar 2018 12:03:36 GMT

I was recently writing a script that performs tasks that take time. I wanted a way to show the status to the user on a single line and keep updating the line. There is the Write-Progress cmdlet, but I didn’t want to use that. Playing with the Console is much easier if you use the .NET classes instead of depending on PowerShells own native Cmdlets like Write-host. Turns out things you can use the System.Console class to achieve all kinds of interesting console behaviors. Here’s my script that re-writes the same line with different texts:

# Save this as a .ps1 file, and execute it using powershell

#
# Function to implement Same line printing
#
function Update-ConsoleLine ( 
    # Message to be printed
    [Parameter(Mandatory = $True, Position = 0)] 
    [string] $Message,

    # Cursor position where message is to be printed
    [int] $Leftpos = -1,
    [int] $Toppos = -1,

    # Foreground and Background colors for the message
    [System.ConsoleColor] $ForegroundColor = [System.Console]::ForegroundColor,
    [System.ConsoleColor] $BackgroundColor = [System.Console]::BackgroundColor,
    
    # Clear whatever is typed on this line currently
    [switch] $ClearLine,

    # After printing the message, return the cursor back to its initial position.
    [switch] $StayOnSameLine
) 
{
    # Save the current positions. If StayOnSameLine switch is supplied, we should go back to these.
    $CurrCursorLeft = [System.Console]::get_CursorLeft()
    $CurrCursorTop = [System.Console]::get_CursorTop()
    $CurrForegroundColor = [System.Console]::ForegroundColor
    $CurrBackgroundColor = [System.Console]::BackgroundColor

    
    # Get the passed values of foreground and backgroun colors, and left and top cursor positions
    $NewForegroundColor = $ForegroundColor
    $NewBackgroundColor = $BackgroundColor

    if ($Leftpos -ge 0) {
        $NewCursorLeft = $Leftpos
    } else {
        $NewCursorLeft = $CurrCursorLeft
    }

    if ($Toppos -ge 0) {
        $NewCursorTop = $Toppos
    } else {
        $NewCursorTop = $CurrCursorTop
    }

    # if clearline switch is present, clear the current line on the console by writing " "
    if ( $ClearLine ) {                        
        $clearmsg = " " * ([System.Console]::WindowWidth - 1)  
        [System.Console]::SetCursorPosition(0, $NewCursorTop)
        [System.Console]::Write($clearmsg)            
    }

    # Update the console with the message.
    [System.Console]::ForegroundColor = $NewForegroundColor
    [System.Console]::BackgroundColor = $NewBackgroundColor    
    [System.Console]::SetCursorPosition($NewCursorLeft, $NewCursorTop)
    if ( $StayOnSameLine ) { 
        # Dont print newline at the end, set cursor back to original position
        [System.Console]::Write($Message)
        [System.Console]::SetCursorPosition($CurrCursorLeft, $CurrCursorTop)
    } else {
        [System.Console]::WriteLine($Message)
    }    

    # Set foreground and backgroun colors back to original values.
    [System.Console]::ForegroundColor = $CurrForegroundColor
    [System.Console]::BackgroundColor = $CurrBackgroundColor

}

# Examples:
Update-ConsoleLine "Beginning process..." -ForegroundColor "White" -StayOnSameLine -ClearLine
Sleep(1)
Update-ConsoleLine "Progress: [..........]" -ForegroundColor "DarkGray" -StayOnSameLine -ClearLine
Sleep(2)
Update-ConsoleLine "Progress: [ooo.......]" -ForegroundColor "DarkGray" -StayOnSameLine -ClearLine
Sleep(2)
Update-ConsoleLine "Progress: [ooooooo...]" -ForegroundColor "Cyan" -StayOnSameLine -ClearLine
Sleep(2)
Update-ConsoleLine "Progress: [oooooooooo]" -ForegroundColor "Green" -StayOnSameLine -ClearLine
Sleep(1)
Update-ConsoleLine "Process Completed." -ForegroundColor "DarkGreen"
Update-ConsoleLine "Begining Next process..." -ForegroundColor "DarkGreen"

Note that this code does not work when you copy paste this on the console and execute it line by line. It also does not work within PowerShell ISE, or VSCode. You have to run it as a script to see it in action. Hope this helps!

Taking a dump of a VM running on Hyper-V

Vimal Shekar — Sun, 23 Nov 2014 00:54:00 GMT

If you have contacted Microsoft support for Virtual Machine hang issues, you would be familiar with the vm2dmp tool. This tool lets you convert a Hyper-V Virtual Machine snapshot to a memory dump, which can then be analyzed to root cause the hang. vm2dmp is a nifty tool, but unfortunately the tool is no longer available for download.

Looking for alternatives? Then read on :

The easiest way to take a memory dump of a VM running on a Hyper-V host, is by using this free Microsoft Sysinternals tool called livekd.exe. For those of you who are not familiar, livekd is an awesome tool that lets you live kernel debug your machine. It runs the same commands you would use on kernel debuggers like windbg and kd when they are attached to a debuggee/target. However the advantage is that livekd can attach to the same host machine from where you are running livekd. For more information on debugger check out this channel 9 video : https://channel9.msdn.com/Shows/Defrag-Tools/Defrag-Tools-22-WinDbg-Memory-Kernel-Mode.

Installing liveKD:

First download and install the Debugging Tools for Windows package from Microsoft's web site: http://www.microsoft.com/whdc/devtools/debugging/debugstart.mspx
Then download livekd from http://technet.microsoft.com/en-us/sysinternals/bb897415.aspx.

Note:

If you install the tools to their default directory of \Program Files\Microsoft\Debugging Tools for Windows, you can run LiveKD from any directory. Otherwise you should copy LiveKD to the directory in which the tools are installed.

If you haven't installed symbols for the system on which you run LiveKD, LiveKD will ask if you want it to automatically configure the system to use Microsoft's public symbol server.

To Configure the symbol path manually, follow these steps:

Create a folder to cache symbols in. For Ex: C:\PublicSymbols
Start > run > sysdm.cpl
Go to the Advanced Tab > Environment Variables.
Under user variables, click New.
Give the variable name as : _NT_SYMBOL_PATH
Give the variable value as: srv*C:\PublicSymbols*http://msdl.microsoft.com/downloads/symbols

Taking a dump of a running Virtual Machine:

Open a command prompt and navigate to the folder where you copied livekd to.
Run the following commands:

livekd -hvl

This command will list all the virtual machines running on that host

livekd -hv -p -o C:\Memory.dmp

This will pause the specified VM and then generate a dump of the VM to the path specified.

Hope this helps!

Using Event viewer custom views for troubleshooting

Vimal Shekar — Wed, 15 Oct 2014 04:00:00 GMT

Recently a customer came to us with a request. He was managing a print cluster and wanted a way to track information about print jobs, when are they spooled, rendered and completed. I did some testing and found that Windows already logs all that information, all he needed to do was to enable PrintService Admin logging and then create a custom view for it. Here are the steps we shared with him :

Information about job spooling time, rendering time, job print complete time is logged into event IDs 800, 805, 307 in the PrintService Operational logs. You will need to enable the logging for this to work :

To enable this logging, go to: Event Viewer > Applications and Service Logs > Microsoft > Windows > Print Service > Operational
Right click and choose "Enable log". If the logging is already enabled, then you may see "Disable Log" in place of "Enable Log".

To create a custom view in event viewer :

Save the following lines as a .xml file.

True
Microsoft-Windows-PrintService/Admin,Microsoft-Windows-PrintService/Debug,Microsoft-Windows-PrintService/Operational
Microsoft-Windows-PrintService
0
307,805,800

Open Event Viewer. Right click "Custom Views" and choose "Import Custom View".
Now point at the xml file you created and click ok.

You are all set. The events will be filtered the next time a print job is given. Hope this helps someone else!

Regards,

Vimal

My First Blog post - (Hurray!)

Vimal Shekar — Tue, 11 Mar 2014 18:32:37 GMT

Hello everyone,

I just got my blog created on MSDN - Welcome to Vimalsdesk !!

Who am I ?

My Name is Vimal, I started off as a Support Engineer with the Windows Core team at Microsoft in 2009. After a year and half, I joined the Beta support team for Windows 8 and 8.1. Currently I am currently working as an Escalation Engineer here with Windows Serviceability team (earlier called Global Escalation Services or CPR team). For more details about my team and what we do - check our team blog here.

Why am I here?

That's something I haven't completely decided upon yet. I am not entirely new to blogging, I do have a few blogs from the time I was a Beta Engineer for Windows 8, you can see some of them here. For now I want this to be a platform to share my experiences while we debug and troubleshoot issues on Windows issues reported to our support teams here at Microsoft. I want to share tips and techniques you can use to troubleshoot issue and reduce your support calls.

How often will you see a post?

I have to set expectations here. We have a very busy work life here, so the frequency of blog posts would be inversely proportional to the case volume we get in our team. So if you want to see more blogs, you should help us by not calling Microsoft Support for every single issue. Start
using Bing's Smart Search more often, and chances are - you will find a solution to your problem on one of our blogs or forums.

Disclaimer:

Blog postings are provided as is with no warranties, and confer no rights. In no way is this meant to be a replacement for support. I only post some tips and tricks for debugging some of the issues - from the perspective of an engineer supporting the product within Microsoft. I hope it is a good source of information for anyone debugging Windows.

That's it for now. I'll be back with some content soon.

- Vimal