Category: Powershell

Amy Herold has scraped PASS Summit 2017 submissions using Powershell:

Never having done a web scrape before, this was the perfect subject for my first time – grabbing all the sessions submitted to PASS Summit 2017…and doing it with PowerShell! Here is the script I used for this. I have accounted for the following:

• Apostrophes (aka single quote). They will break your insert unless you have two of them, and for some reason, people seem to use them all over the place.

• Formatting the string data for insert. No, your data will not magically come out right in your insert with single quotes so you need to add them.

• Additional ID and deleted fields.

• Speaker URL and ID. Will be using this to scrape speaker details later.

• Accurate lower and upper bounds. These were arrived at by trial and error (you’re welcome), as well as the clean up of the data I scraped. More on this later.

Powershell probably wouldn’t be my first language for web scrapes—that’d be Python—but Amy shows how to get a scrape going.

Adam Bertram explains the difference between the where-object and the where method in Powershell:

The Where-Object command is a sort of generic filtering command. Use this command to filter any kind of object in PowerShell. The Where-Object command has a FilterScript parameter, which is a scriptblock that allows the user to place code in it. If this scriptblock contains code that returns anything but $false, $null, or an empty string, it will allow whichever object the user passes to it.

For example, let’s say I’ve got a folder full of files. I’d like to see only text files and only those text files modified today. To make this happen, I can use the provider-specific filter with the Get-ChildItem command and also the Where-Object command.

Read on to see how that compares to the where method.  Given the latter’s limitations, I’ll probably stick to where-object anytime performance is not critical.

Claudio Silva shows how to re-run statements in your Powershell history:

While we were running some commands we talked about Get-History cmdlet.

For those who don’t know

this cmdlet lists all the commands that you already ran on the current session.

I wondered if it is possible to pipe the Get-History output and run it again. I could bet yes but I never tried before.

The answer is that yes, you can, and Claudio shows how.

Richie Lee has a method for checking whether a variable exists in Powershell:

Recently I needed to check that a variable exists in the PowerShell session currently running. This is actually far easier than it sounds. So here is a simple demo for how it works. The magic here is the “Test-Path variable:my_variable” on lines 4. It tests that a variable of that name exists. If it does, great, let’s print out the value. If not, let’s alert that it doesn’t. The second example of this on line 11 will do exactly that.

Read on to see Test-Path in action.

Amy Herold has a quick Powershell script to retrieve detailed system info (via msinfo32.exe) for a set of servers:

With this script you can generate system information files and save them to a specified location. It makes sure a connection can be made to the server first, and then outputs the file. The files are created one at a time, so if you pass in a longer list of servers, you shouldn’t crash your machine. From my testing, this will take some time to run as these files don’t output quickly. Despite that, the output is worth it. This can be modified to pull your list of servers from a file or from a Central Management Server (CMS) instance.

This is a useful script, with the next step being to turn it into a cmdlet that accepts the set of servers from the pipeline.

Jana Sattainathan has some thoughts on when to use each of the Write- cmdlets in Powershell:

PowerShell has matured as the automation tool of choice on the Microsoft platform, be it on Windows or Azure. However, there is no official guidance on best-practices and standards around some things. At times, bloggers do things incorrectly in their examples thereby reinforcing bad practices. Hopefully, this small post will help connect some dots for you! Please comment if I am stating something that is not a generally accepted best practice. Specifically, we are going to glance at the following cmdlets

• Write-Host

• Write-Output

• Write-Debug

• Write-Warning

• Write-Error/Throw

• Write-Verbose

• Write-Progress

Write-Host is the easiest and probably most controversial of the set (because its messages are outside the pipeline), but there’s a place for each of these.