BASH – Determining that a variable is empty

Hi everyone

Today I had to script a bit inside a Linux VM on Azure. I had to make some test inside a bash script. To my extent I’am not a Linux expert, but I wanted to share a small tip I found.

How to find is a variable is empty or unset in BASH ?

To find if a variable is SET to empty to a “” string please use the comand :

if [ -z “$VAR” ];

Another way to write it would be with double bracket :

if [[ -z $var ]]
if [[ -z “$var” ]]
if [[ ! $var ]]
if [[ ! “$var” ]]

or that expression would check if it’s with a value :

if [[ $var ]]


Thanks everyone, enjoy the small tip

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Can’t open the MMC .. “MMC can’t open C:/Windows/System32/services.msc”

Hi everyone !

Today I wanted to share a quick and handy tip.

If you are stuck with a bug that your MMC don’t want to open, services.msc in my example, don’t forget you can clear the MMC cache to give it a chance to re-open.


To fix it open up MMC.exe, and select that; File->Options->Disk Cleanup->Delete Files


After that the MMC would load more easily and most of all without errors.


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PowerShell Tip: Active Directory Module not found

Hi everyone

I wanted to share a small tip if you still manage older active directory server with powershell.

I stumbled into a Domain Controler today that hasnt the PowerShell’s module for ActiveDirectory, I was wondering why, and found out it need to be added as a feature.

We can see the error there when we try to import the module;


If it happen to you, be sure its added as a feature there;


and you select Active Directory for Windows PowerShell there;


Tomorrow I will share a small PowerShell script handy to clean up your Active Directory objects !




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Microsoft Chromium Edge now available for Windows 10 LTSB, and soon for others OS !

Hi everyone

I wanted to share a good new, Chromium Edge is now available for Windows 10 IoT/LTSB’s build ! We can now finally enjoy it with that build used in enterprise mainly.

You can go get it there ! ( )

A plan is there to make it available for older and other OS too. even for the macOS.

Microsoft Edge will now be delivered and updated for all supported versions of Windows and on a more frequent cadence. We also expect this work to enable us to bring Microsoft Edge to other platforms like macOS

A picture of it running at my home lab 🙂


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Roaming profiles and system tray icon cache error

Hi all !

Today I will share a small tip to resolve when the systray act strangely with the icon cache.

The display I had was like that;


The problem seem to be with a corruption in that registry key value;

HKCU\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\TrayNotify


The fix is simply to delete those two keys; with a script like that one;

reg delete "HKCU\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\TrayNotify" /v IconStreams /f

reg delete "HKCU\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\TrayNotify" /v PastIconsStream /f


If you use roamings profiles it can become harder to fix, as it can be a widespread problem.

To resolve the issue I added a local user GPO the machines that are using the roaming profiles, as such all the profile will be corrected. I didn’t used a domain user gpo, as the registry fix must be invoked before explorer.exe start, so I get a better result in a local user GPO.



After that tip, all my systray icons are back to normal 🙂

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RDS: HP Thin OS resolution problem in Full Screen mode !

Hi everyone

Today I wanted to share a small error I found into the HP thin client that has the Thin OS.

The error impact that RDP setting when you create a RDP connection;


The resolution can bug on the setting page. You ask me what bug it can cause ? well if you do a RDP’s session in fullscreen mode, the user will think they use a resolution X, but in reality the terminal server will see the correct resolution Y.

The bug happen with different display adapter or monitor.

The Thin OS seem to detect the possible resolution from the monitor and limit the choice, but the GUI is not limited to that list. xrandr offer a list while the GUI offer the full list.

As you can see in that printscreen is that exact problem, I set 1280×768 into the left windows, no error, and it’s set, but in the right windows we see the current resolution is 1920×1080 and 1280×768 is not possible..


The tip is to issue an xrandr command to see what we can use;


and to set it to one of those resolution..

For me it’s a bug, as if you manually set the resolution with xrandr, like in my example 1280×768 that I tried without success with the GUI, but it work if I set it with xrandr by hand.. but no config file are possible to change to add an custom mode resolution.. So the change is lost on reboot.

Enjoy the small tip, got me some time to manage that the GUI is in error.

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Unable to rename domain controller: Account already exists

Hi everyone

I seen an interesting bug yesterday, it was about Windows Server 2019 and a error when you try to rename a new domain controller to the old name of a retiered’s one;

The error Windows was giving was:

The account already exists.

The culprit into that case was a left over that was visible in ADSI Edit. The exact location was;

Configuration -> CN=Sites -> CN=Default-First-Site-Name -> CN=Servers -> CN={Old Domain Controller}.


As simple as that, but it need a bit of playing in ADSI Edit 🙂


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