In this post we will be going through using if else statements.

If else statement in PowerShell evaluates a condition and executes code if the condition is true. If the condition is false, alternative code is executed.

If else can also be nested to create more complex scripts that handle multiple conditions and execute specific code for each condition.

If else follows the below format

if (condition) {
    # code to execute if condition is true
} 
else {
    # code to execute if condition is false
}

If Statement

We will first go through using a single if statement, when using a if the part between the two () is the conditions which needs to be checked.

When using an if without an operator (eq, like, gt…..), the if will check that the variable is not empty.

The below shows the difference between the if statement when there is a value and no value.

When using an operator we can specify if the value matches then run the code.

$con = "True"
if($con -eq "True"){
    Write-Host "Con is true" -ForegroundColor Green
}

If Else

Next we will go through using if and else. Adding else is a way to executed code if none of the conditions are meet.

$con = "True"
if($con -eq "True"){
    Write-Host "Con is true" -ForegroundColor Green
}
else
{
    Write-Host "Con is false" -ForegroundColor Red
}

We can add an elseif to add another condition, there is no limit to how many can be added but it can be a bit messy if there are two many if elseif’s. Also the first condition that is meet is will stop the rest from being tested.

$con = "True"
if($con -eq "True"){
    Write-Host "Con is true" -ForegroundColor Green
}
elseif ($con -eq "False") {
    Write-Host "Con is false" -ForegroundColor Red
}
else
{
    Write-Host "Con does not meet condition" -ForegroundColor Yellow
}

If with additional operator

We can test multiple conditions by using different operator in the if statement. In the below we are using the -and operator to check that condition one is true and condition two is greater than 3

We can also use -or operator which allows for us to specify two expressions and returns true if either one of them is true.

$con1 = "True"
$con2 = "5"
if ($con1 -eq "True" -or $con2 -gt "6"){Write-Host "Condition are meet" -ForegroundColor Green}

If Null

We can also check for Null values in If statements, to check if a variable or result is null we use the $null variable.

The $null variable must be on the left side of the statement as if it not PowerShell may not

Using if statements in your PowerShell scripts creates a lot of possibilities for creating dynamic and responsive automation. They can be a bit confusing at the start but with a bit of practice and experimentation, if statements become powerful tools in your scripting.

In this post we will be going through the different types of loops in PowerShell.

There are a few different types of loops and we will go through each and showing examples on how to use them. Loops are very useful and will be required in most scripts.

The first we will go through is a ForEach-Object loop, this is one of the main loops I use and can be used a few different ways.

Foreach Objects

First way is to get a list of objects and then pipe to our foreach-object to go through each.

Below example will get all services, loop through the results and return each name.

Get-Service | ForEach-Object { $_.Name}

Another method for using foreach-object is to use a variable with a set of object or a command that will retrieve objects and loop through each object in the variable.

There are two short hand commands for foreach-object, % and foreach.

In the below I am getting all folders under the directory and adding them to a $folders variable and looping through each.

$folders = Get-ChildItem C:\temp\ -Directory
foreach ($folder in $folders){$folder | Select-Object Name,CreationTime}

We can also use the foreach method on the variable to loop through the objects.

I mostly use foreach in my scripts as I find it the easiest to read when I have to go back over my own scripts.

While Loops

The other type of loops is a while loop.

Do while basically mean that while a condition is true the script will then keep looping.

This can be useful if we want to run a script for a certain period of time or while a process is running.

Below will loop through till the number in the variable $i is 10 then it will run the second write host.

$i = 1;
Do {
    Write-host "is $i less then 10" -ForegroundColor Red
    $i++;
}
While ($i -lt 10)
Write-Host "is 10 or greater" -ForegroundColor Green

Next we will go through do until, the different between do while and do until is that while uses true and until uses false condition.

This could be used if we wanted to check if a certain number of files or in an install script we could wait for certain process to finish before completing the next part.

Below example I am using a do until on a folder to check how many logs are there and using a do while to create the logs.

Check logs count.

Do {

    $logs = Get-ChildItem -Path C:\temp\Logs
    Start-Sleep 5
    Write-Host "Less than 10 logs found" -ForegroundColor Green
}
Until ($logs.count -gt "10" )
Write-Host "More than 10 logs found" -ForegroundColor Red

Create logs files.

$i = 1;
Do {
    New-Item "C:\temp\Logs\Log$i.log"
    $i++;
}
While ($i -lt 10)

This has been overview of some of the different types of loops and how to use them. There are pros and cons to using each and the right one to use will really depend on what the script is being used for.

In this post we will be going over filtering in PowerShell and different methods available.

Filtering should be done as close to the source command as possible, this will speed up the time it takes for the command to complete and return the data.

Depending on the command used there can be a filter parameters available, if there is no filtering we would use where-object.

Where-Object can be used to filter objects based on any property that is returned from the command.

If we need help with example or the right syntax to run the command we can use

Get-Help Where-Object

Get-Help Where-Object -Examples

Where-object can be used with lots of filtering parameters to return objects like Contains, eg (equal to), gt (greater than), lt (less than), like…….

https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/where-object?view=powershell-7.4#parameters

Once we have the syntax worked out we can start to filter the data to returned. In the below command we will return any file that has .pdf extension and just select the name to make the results easier to read.

Get-ChildItem -Path 'C:\Program Files\' -Recurse -File | Where-Object {$_.Name -like "*.pdf"} | Select-Object Name

Get-ChildItem has a filter parameter, this allow us to test and show the speed difference when we can.

Below is the time when running the command using where-object.

When we use the -filter with Get-ChildItem we can see that the time to run went from 6 second to 2 seconds.

This was only a small subset of data but if we where running against thousand or hundred of thousand of files this can add up and save minutes to hours of time for data to returned.

In this post we will be going through the use of variables, arrays and hash table.

Variables are object that are created temporarily in the PowerShell console or created as part of script that are removed once the console is closed. There are system variables that are part of PowerShell but we will just be covering user variables in this post.

Variables are $ sign with a name.

We can then call the variable by using the name

There are two type of quotation marks single will only display the text between the quotes. We can use these for variable that have text data.

With double quotation marks we can passthrough text but also passthrough a variable. If we try to add a variable without double quotes it will just write the variable name and not the text in the variable.

There are some instance where we need to create a subexpression using $() around the variable to pass through specific data.

In the below I want to return just the first folder. The first command return all the folder names.

The second command is using a subexpression, we are then able to return the first folder name.

An array is pretty similar to a variable the only really difference is that it has multiple objects broken up by using comma’s.

We can also use @() to create any array if there is text other than number we have to use quotes.

We can also create a blank array, I use these when doing reports and want to output data from a script.

We will go more in depth on using the blank array in a future post but I mostly use them with hash tables.

Next we will go through using a hash table, these are like array but there is key / value pair.

Below we have a table where we created a name, surname and role heading and set a value for each.

We can also use array or variables in hash tables

This is where hash tables can come in hand for doing reports as we can output the results of multiple commands using a blank array and a hash table, then export the results to a CSV, text or html file.

We will cover both these in later post.

In this post we covered create variables, types of quotes and there uses, array’s and hash tables with some examples of each.

In this post we are going to go through sorting, selecting and formatting object data.

To be able to get the right information back in both the PowerShell console and to output to files like txt, csv, html…, it’s import to be able to format the data correctly.

We can sort by using sort-object command, in the below example we can see that the process are sorted by process name by A to Z.

Now we can use sort-object to sort the processes by ID instead of name.

We can added -descending to sort from other way either.

There can be hidden properties that can be useful, to view these we can use the Get-Member and use member type property.

Get-Process | Get-Member -MemberType Property

We can now use the property names with select-object to return the additional properties.

Select-Object has a first and last parameters that let you skip everything but the specified number of objects.

Using the below will only return the first 20 processes.

Get-Process | Select-Object -First 20

Using calculated property in Select-Object is a good way to rename a properties or use math’s to work out a value like the size of a folder or memory used by a process.

To create a calculated property we use @{Name=”Name of property”;Expression={$_.propertyname}}.

Get-Process | Select-Object Name, CPU, @{Name="Memory";Expression={$_.WorkingSet/1KB}}

In the next post we will be going through Variables, Arrays and Hash Tables

In this next series of post we will go through getting start with basic commands, more advances commands and then going through how to use these to creating more complex scripts.

First cmdlets in PowerShell are named according to a verb-noun naming (mostly, there are times when people create there own command that don’t use the verb-noun naming). This pattern is to help give an understanding of what the command does and how to search for them.

Sometimes finding the specific command you want is time consuming in PowerShell. This is where the Get-Command command can come in handy

If we want to find a command by name we can use the full name

If we don’t know what the command is we can use wildcard (*) to return all command that have a conmen name.

Below example returns all command that have network in the name.

Once we have a command we can either look up the documentation or use Get-Help to view how to use the command and examples.

To view the full help with examples on how to use.

Get-Help Get-Service -Full

To view just the examples

Get-Help Get-Service -Examples

To open the webpage for the command use -Online

Get-Help Get-Service -Online

Below is a quick overview of what each verb function should be.

To return a list service’s we can run Get-Service.

If we want to filter to only return service with specific status like running we can use where-object and the status property.

If we wanted to only return the display name and status we would pipe the result using | and then use Select-Object.

If we know there is a certain restart order for an application or a restart of a service will fix a specific issue on server or endpoint device, we could then use the name and status to start or restart the service.

To run remotely (if the command supports remote calls) we an use the ComputerName (sometimes its Server, depends on the command).

In the next post we will look at sorting, selecting and additional properties of Objects in PowerShell.