Windows PowerShell Examples
Examples to Illustrate Windows PowerShell Basics
While PowerShell has all the complexities of leading scripting language, it is particularly easy to pick up the basics. To see how friendly PowerShell is for the novice try my simple examples on this page.
Basic PowerShell Examples: Finding Files
PowerShell Pre-requisites and Checklist
In the case of Windows 7 and later, you don't need to download any extra files, just: 'Add Feature' --> Windows PowerShell. However, for older operating systems, there are different versions of PowerShell for XP, Windows Server 2003 and Vista. For such legacy systems only, you need to download PowerShell from Microsoft's site.
Once you have installed PowerShell 2.0 or later, I recommend choosing the ISE (Integrated Scripting Engine) version, it will save buying a text editor.
While Example 4 will list all the files in the Windows directory and then sort them into order of the most occurrences of the word 'Error', let us begin with a basic example.
# Basic PowerShell example to find Windows log files
Note 1: The first point to remember about PowerShell is that the cmdlet is the basic building block for more complex scripts. In this instance note the rhythm of the verb noun pair Get-ChildItem.
Note 2: Incidentally, this simple construction (C:\Windows\*.log) is much faster than (C:\Windows\* -Include *.log). You will see the difference when we ask -recurse to drill down to the sub-directories in Example 3.
Windows Management Instrumentation (WMI) is one of the hidden treasures of Microsoft's operating systems. Fortunately, SolarWinds have created a Free WMI Monitor so that you can discover these gems of performance information, and thus improve your PowerShell scripts.
Take the guess work out of which WMI counters to use when scripting the operating system, Active Directory, or Exchange Server. Give this WMI monitor a try - it's free.
While experienced PowerShell users won't admit it, everyone sneaks a look at Get-Help when they research a new cmdlet. My purpose in introducing Get-Help is to reveal the secret of how I learn about PowerShell.
# PowerShell Basics: Get-Help for Cmdlets
Note 3: Actually, plain 'Help Verb-Noun' also works because 'Get' is the default verb and PowerShell assumes that what you meant, for instance try: 'Help Get-ChildItem'. Talking of assumptions PowerShell assumes that first instruction is for the location, thus you don't need to explicitly use the -path parameter in most Get-ChildItem scripts.
Note 4: The point of calling for help is to seek useful -parameters for your project (Some people call them switches). In this case -recurse, -Include and possibly -force are important modifiers for the main Get-ChildItem cmdlet.
Note 5: I don't know why you would ever call for Get-Help without appending its -full parameter. What this does is give you examples of how apply the particular cmdlet.
By getting to know the parameters you can solve problems, for example by employing -Include and -recurse in tandem you can list all the log files under the Windows folder.
# PowerShell example to find Windows log files
Note 6: One reason that I used the variable $Directory is that I wanted to remind you to change the value of the path before adapting this script to another PowerShell project.
Note 7: Backtick (`) is PowerShell's word-wrap, it means continue the same command on the next line.
Note 8: The CommonParameter '-ErrorAction SilentlyContinue' permits Get-ChildItem to cope with log files which are in use. To see what I mean, try the above script without the last line.
SolarWinds' Network Performance Monitor will help you discover what's happening on your network. This utility will also guide you through troubleshooting; the dashboard will indicate whether the root cause is a broken link, faulty equipment or resource overload.
What I like best is the way NPM suggests solutions to network problems. Its also has the ability to monitor the health of individual VMware virtual machines. If you are interested in troubleshooting, and creating network maps, then I recommend that you try NPM now.
Example 4: PowerShell Real-life Task - Find Windows Log Files With 'Errors'
The scenario is that we want an overview of our Windows log files. Time is short so we just want a list of the files which contain the most 'Errors'. Incidentally, if you try this script for real you will be shocked at how many errors there are in your Windows operating system.
# PowerShell example to find and sort Windows log files
Note 9: Compared with Example 1 this represents a huge leap in complexity. The secret of unravelling how it bolts together the elements is to look for the (|) pipes. The vertical bar (|) is PowerShell's signature tune, it pipes the output of the first command into the second phrase, and then output of the second phase into the third part.
In this instance, once 'Get-ChildItem' supplies its list of log files, Select-String filters this stream, then passes it along the chain for grouping and sorting.
Note 10: See more on ErrorAction control methods.
Where Next? More PowerShell Examples
Summary of PowerShell Basics
While PowerShell has all the complexities of leading scripting language, it is easy to get started. The first point to remember about PowerShell is that the cmdlet is the basic building block. The secret of success is to remember the rhythm of Verb-Noun, for example Get-Help, or Get-Childitem. It is possibly to learn the basics just through trying my PowerShell examples.
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Please email me if you have a better example script. Also please report any factual mistakes, grammatical errors or broken links, I will be happy to correct the fault.