It appears many of you are taken with the possibilities of PowerShell prompt functions. In previous posts, I alluded to the fact that you could do just about anything in a prompt function. Today I have an example of what I am talking about. The challenging part of creating a prompt function that does more is that you want it to run very, very quickly. The last thing you want is to wait several seconds for your prompt to return. With that in mind, here\u2019s a prompt function that will display is a small list of servers is up or down.<\/p>\n
When I first started working on this I was calling Test-WSMan<\/a> to verify if 4 computers were up and running. However, this took a few seconds per server which made the entire prompt function frustratingly slow. I toyed with the idea of running the test in a background job and displaying the results of the last job, but this too was very slow. Then I hit on the idea of using a runspace and a synchronized hashtable.\u00a0 This is an advanced topic so don\u2019t feel bad if you don\u2019t follow everything.<\/p>\n Think of the runspace as a separate and hidden PowerShell window. In the runspace, I\u2019m running code to \u201cping\u201d the servers with Test-WSMan every 5 seconds. That seemed like a reasonable amount of time. My prompt function is not intended as a high availability solution. The runspace updates a hashtable variable that is synchronized with my console session. This means I can access the hashtable and update my prompt function. The code for this function can be found on Github<\/a> or you can copy it from here.<\/p>\n