Category: Powershell

Steve Jones warns us away from Write-Host in Powershell:

I’ve written a few scripts and programs lately, mostly just for fun. In those scripts, I’ve used Write-Host to return output. To me, it’s been like “Print” in various languages where I can get output of a program. Often I’ll use a method/function to get info and then use print to output that to the caller.

However a few people noted that in my last script, Write-host wasn’t necessary. When I asked why, both Mike Fal and Drew Furgiule responded.

Mike and Drew are smart cookies.  Write-Host has some major limitations which hinder developers’ abilities to modularize and package viable code.

Richie Lee shows off Get-TimeSpan and New-TimeSpan:

As is the case with most things, when I find a way for getting something done in a script that is “good enough”, I’ll tend to stick with that method until that method no longer becomes fit for purpose. One such method is printing out the time that something took in PowerShell: many of the scripts on my site use this method to get the duration of a task, and I’ve been using this since PowerShell 1.0

This is certainly an improvement over the old version.

Mike Fal shows us how to get database file information using Powershell:

To do this, I dove into the SMO object model. This gets a little /Net-y, but the good news is there’s lots of properties we can use to get the information we are looking for. If we look at both the DataFile and LogFile classes, there are properties readily available for us. Both classes have UsedSpace and Size properties (both measured in KB), from which we can derive both available space and percentage used. All it takes is wrapping some collection and formatting logic around these objects and we’re good to go. You can see my full function up on GitHub.

This is a nice example of using the Powershell pipeline to build an end product, in this case an HMTL report of log and file usage.

Cody Konior shows how to use GetDefaultInitFields in SMO to improve performance, and also explains a bug when you try to do this:

It turns out has no default properties set, and the exception seems to occur after you try to set some. Interestingly though the way that boolean flag works is to set default properties on each SMO type; which means the solution is to turn it on for everything and then only disable it for this specific type; retaining any of the performance improvements throughout the rest of SMO.

Anything that makes SMO faster gets a vote of approval from me.

Kenneth Fisher shows us how to generate multiple connections using Powershell:

As with most of these types of things, I had a need. I want to show how using sys.dm_exec_[requests/sessions/connections] is better than sp_who. Particularly when you have a large number of connections. Well in order to do that I need a large number of connections right? Now I’m sure someone out there has a script to generate somewhat random connections but writing one myself would be good practice and I’d like to get better at Powershell anyway. In the end I need some help and as aways it was plentiful and easy to find. So thanks to Derik Hammer (b/t), Drew Furgiuele(b/t), and of course it wouldn’t be a PoSH script if I didn’t get help from Mike Fal (b/t). (To be honest Mike actually wrote most of the final script)

This is great for demonstrations, and with a few tweaks you can turn this into a very poor man’s load tester.

Nicolas Prigent describes Powershell Desired State Configuration:

The management and maintenance of servers quickly becomes complex without standardisation. PowerShell allows us many ways of responding to different problems and occasionally bypassing certain restrictive techniques. The danger is that we end up with a plethora of scripts in order to manage a server, all more complicated than the other, and this works. We do much better with a standard way of automating a task

DSC gives us a declarative model for system configuration management. What that really means is that we can specify how we want a workstation or server (a ‘node’) to be configured and we leave it to PowerShell and the Windows Workflow engine to make it happen on those target ‘nodes’. We don’t have to specify how we want it to happen.

DSC is great for keeping servers and server configurations in sync.

Rob Sewell walks through a Powershell script failure:

Googling pester “The script failed due to call depth overflow.” returned only 7 results but the Reddit link contained the information I needed

For more on the depth call limit, Jon Galloway has a great post.

Mike Fal shows us how to mange SQL Server error logs using Powershell:

Reading SQL Server error logs is pretty simple, but requires us to make use of the SMO objects and the .ReadErrorLog() method to get the data from the log. Let’s start by simply reading the SQL Server error log and see what the output looks like (I’ll be using the SQL Server provider for this)

The big benefit, as Mike points out, is that the log rows are considered objects, meaning you don’t need to try to parse out things like the log date.