Category Archives: PowerShell

A Timely PowerShell Prompt

021913_2047_WordTest1.pngDuring the course of writing a few scripts that refresh a specific part of the console, such as the recent Read-Host alternative, I realized that flashing colors wasn’t always necessary. The fact that I could update the same space on the screen meant I could write the same content with minor changes and it would look like the the screen as “flipping”. Essentially I was thinking of a clock.

So I thought it might be handy to have a clock as part of my PowerShell prompt. PowerShell has a built-in function called Prompt but you can replace it with your own version. The function will only last for as long as your PowerShell session so if you don’t like it, exit and restart PowerShell.

This is for the most part the basic function that shows PS and your current location. This prompt function will not work properly in the PowerShell ISE. The magic happens by always setting the cursor to the same coordinates in the PowerShell shell console. I use the same type of While loop I used in my other functions, only this time I’m waiting for the user to press any key, which would indicate the start of typing a command. Once that has been detected, the looping stops and the time ceases to be refreshed in the prompt.

You really need to see this live but here’s a screenshot example.
time-prompt-1

Then I thought it might be helpful to have the clock stand out so I added a little color.

time-prompt-2

The only issue I’ve found with these prompts, is that if you need to scroll in the console window, you’ll need to press the spacebar or type something so that the clock stops refreshing. Otherwise you are scrolling while PowerShell is trying to write to the console.

Instead of clock you could use a countdown timer. Or perhaps some sort of performance counter. For a prompt though, you need to make sure you can get and display the information in a few hundred milliseconds, otherwise the prompt will feel sluggish and unresponsive.

Enjoy and let me know where this leads you.

More Flashing Fun

talkbubbleI received a lot of interest in my Invoke-Flasher script. One comment I received on Twitter was for a way to use it interactively in a script. In essence, he wanted a flashing Read-Host so I took my original concept and tweaked it until I came up with a Read-Host alternative I simply call Read-Host2. This function will only work in the PowerShell console, NOT the PowerShell ISE.

The main tweak I made was to collect all the typed keys until Enter is pressed. I have a Switch construct to also eliminate the Shift key. The assumption is that you are writing text so this should be the only non alphanumeric key you would use. The message prompt will keep flashing until you start typing. I also emulated echoing text to the screen, including password masking if you use AsSecureString. The last change is a new parameter to allow you to flash the foreground color instead of the background color. There are several examples in the comment-based help.

Here are some screen shots.
Read-Host2-01

Read-Host2-02

I hope you’ll let me know what you think.

Look at Me!

bluelight Last week I posted some ideas on how to add notifications to your scripts. Those ideas were variations on the old school “Press any key to continue” prompt that I assume many of you are familiar with. Most of those concepts should work for you, but they assume you looking at the PowerShell window. I thought about those situations where perhaps I only see a portion of the PowerShell window. Wouldn’t it be helpful if you had some other visual clue, like a flashing light? I thought so and whipped up Invoke-Flasher. I’ll admit the name might have an unexpected connotation, but you can always change it.

Here’s the function, and then I’ll explain how to use it.

This function will only work in the PowerShell console, not the PowerShell ISE because it uses the ReadKey() method from $host.ui.rawui to detect if the user hits any key. The main portion of the function keeps looping through until a key is pressed. Each time through the background color of the host UI is toggled between the current color and Red, or whatever console color you specify. Each time through the script writes your text and “Press any key to continue”. I use the Coordinates property of the host to write to the same spot on the screen each time so there’s no scrolling.

By default, the Write-Host line will “flash” by alternating the background color. Or you can use the -FullScreen parameter which will clear the host everytime. If you use this option in your script, make sure the main part of your script is saving data somewhere because you won’t see it. Here’s an example of how you might use it.

After the main portion of the script completes, the flashing message is displayed after the results. If you want to use the fullscreen approach, you could try something like this:

When the main portion of the script finishes you’ll get a flashing screen with the text message. Press any key and you’ll get the results.

I have to say I’m intrigued by this function and can already think of some ways to improve it. If you have suggestions or find this useful, I hope you’ll let me know.