Category Archives: string manipulation

14Mar/18

PowerShell Tip: Another Take On Progress Reporting

Normally in PowerShell if you want to report progress on a long running task, you’d use a progress bar using the Write-Progress cmdlet. That’s definitely the right way to do this, but what if you wanted a different way… for some reason? In the PowerShell Slack (invite yourself: slack.poshcode.org), I recently answered this question: “I want to write out ‘There are 3 seconds remaining. There are 2 seconds remaining.’ etc. until there are no seconds remaining and then keep going, but I don’t want them all to appear on the different lines. I basically just want the number to update.”

This gif shows what the question asker was after (except instead of counting up, they wanted a countdown).

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21Feb/18

Regex Example: Strip Out HTML Tags

First and foremost, HTML is not regex friendly. You should not try to parse HTML in PowerShell, or using regular expressions unless you’ve lost some kind of bet or want to punish yourself for something. PowerShell has things like ConvertTo-HTML that will make that kind of thing way less migraine inducing.

That said, I recently had a situation where I just wanted to strip all the HTML tags out of a string. My input looked something like this (assigned to a variable $html).

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10Jan/18

PowerShell Regex Example: Incrementing Matches

In the PowerShell Slack, I recently answered a question along these lines. Say you have a string that reads “first thing {} second thing {}” and you want to get to “first thing {0} second thing {1}” so that you can use the -f  operator to insert values into those spots. For instance…

The question is: how can you replace the {}’s in the string to {<current number>}?

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13Dec/17

Formatting Strings In PowerShell Using Fixed Width Columns

Working with strings in PowerShell is fun, I don’t care what you say. In this post, I’m going to show you how to clean up the strings your code outputs, at least in some situations.

Say you have a variable $fileExtensions which you populated with this command.

And, for some reason, instead of the default output which is formatted like a table, I want output presented like this.

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29Nov/17

Beginner PowerShell Tip: Using Variable Properties In Strings

If you’re just getting started in PowerShell, it’s possible that you haven’t bumped into this specific issue yet. Say you’ve got a variable named $user and this is how you assigned a value to it.

Using the Active Directory module, you got a specific user. Now, you want to report two properties back to the end user: SamAccountName and Enabled. The desired output looks like this:

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11Oct/17

What’s the difference between -split and .split() in PowerShell?

Here’s a question I see over and over and over again: “I have a string and I’m trying to split it on this part, but it’s jumbling it into a big mess. What’s going on?” Well, there’s splitting a string in PowerShell, and then there’s splitting a string in PowerShell. Confused? Let me explain.

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13Sep/17

Piping PowerShell Output Into Bash

With Windows 10, you can install Bash on Windows. Cool, right? Having Bash on Windows goes a long way towards making Windows a more developer-friendly environment and opens a ton of doors. The one I’m going to show you today is more of a novelty than anything else, but maybe you’ll find something neat to do with it.

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09Aug/17

Add A Column To A CSV Using PowerShell

Say you have a CSV file full of awesome, super great, amazing information. It’s perfect, except it’s missing a column. Luckily, you can use Select-Object along with the other CSV cmdlets to add a column.

In our example, let’s say that you have a CSV with two columns “ComputerName” and “IPAddress” and you want to add a column for “Port3389Open” to see if the port for RDP is open or not. It’s only a few lines of code from being done.

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28Dec/16

Does A String Start Or End In A Certain Character?

Can you tell in PowerShell if a string ends in a specific character, or if it starts in one? Of course you can. Regex to the rescue!

It’s a pretty simple task, actually. Consider the following examples

In the first two examples, I’m checking to see if the string ends in a backslash. In the last two examples, I’m seeing if the string starts with one. The regex pattern being matched for the first two is .+?\$ . What’s that mean? Well, the first part .+? means “any character, and as many of them as it takes to get to the next part of the regex. The second part \\ means “a backslash” (because \ is the escape character, we’re basically escaping the escape character. The last part $ is the signal for the end of the line. Effectively what we have is “anything at all, where the last thing on the line is a backslash” which is exactly what we’re looking for. In the second two examples, I’ve just moved the \\ to the start of the line and started with ^ instead of ending with $ because ^ is the signal for the start of the line.

Now you can do things like this.

Here, I’m checking to see if the string ‘bears’ ends in a backslash, and if it doesn’t, I’m appending one.

Cool, right?

26Oct/16

Quick Tip: Get All The Security Patches Installed On A Server Since A Specific Date

Recently, I needed to get a list of all the security patches I’d installed on a group of servers in the last year. It turns out that there’s a WMI class for this and it’s super easy to retrieve this info.

In the win32_quickfixengineering class, you’ll find all the security patches installed on a system. One of the properties is the InstalledOn attribute which more recent than a year ago.

If you have a list of servers to do this for, this is still really easy.

Just paste them into a here-string and execute this for each of them.