powershell-scripting-cheatsheet

Basics of PowerShell Scripting

Beginning with the basics of the PowerShell

    $PSVersionTable

The First command that we have is: here
Displays details about the version of PowerShell that is running in the current session.

    Get-Process

The Output for the same is here
Displays details about all the processes currently running on the system. This is a cmdlet

    Get-Service

The Output for the same is here
Displays details about all the services currently on the system and their state whether they are running or stopped. For Example: Background Intelligent File Transfer Service is used for file transfer
This is a cmdlet

    Get-Date

The Output for the same is here
Displays the current Date and Time This is a cmdlet

    Get-ChildItem

The Output for the same is here
Displays all the current files and directories of the current working directory, just like a 'cd' or a 'ls' command This is a cmdlet

If you have noticed carefully the Get-ChildItem cmdlet works exactly like the 'dir','ls'.
So why we have all the three of them?🤔

Get-ChildItem is a cmdlet, whereas 'dir','ls' are its aliases. Aliases are nothing but the identifier to the cmdlets.
We create Aliases for our ease to remember any specific cmdlet with our identifiers.
We use Get-Alias command to display all the aliases present on the current system.
Get-Alias is a cmdlet.

    Get-Alias

The Output for the same is here
The output shows o/p of 2 commands the first one is cmdlet - Get-ChildItem and the second is alias - dir.
Another comman alias - cd is equivalent to Set-Location. Example

    Get-Alias < alias-name >

Checks if the alias exists, if yes displays the output
This is a cmdlet but it gets the info about the alias

    help < alias-name >

Checks if the alias exists, if yes displays the details of the alias.
This is a cmdlet but it gets the info about the alias

    new-alias -name < alias-name > -value < corresponding-cmdlet >

The above command is used in creating your own alias as per your needs. Example of the alias.
This is a cmdlet but it is used to create the alias

    Remove-Item Alias:< alias-name >

The above command is used in removing an alias. Example.
This is a cmdlet but it is used to delete the alias

set execution policies

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned

Get Execution Policy

Get-ExecutionPolicy

$fName =$args[0]
$lName = $args[1]
write-Host "Hello Butch"
Write-Warning "$fName $lName"

write-host "First write"
write-host "This is your computer logged in from $env:COMPUTERNAME"
write-host "Mogambokhush hua"
Get-ExecutionPolicy

To get a full name or to get the full output we can use

Get-Service | Format-Table -Wrap

If in place of table we want the same thing as list, then

Get-Service | Format-List

$varname = get-service -name Bits | select name, status
write-host $varname

Get-Service | select -property name,starttype

(get-service|?{ $.Status -eq "Stopped" -and $.StartType -eq "Automatic"})| select DisplayName, StartType, Status

Get-Service | Select-Object -Property Name,Status,StartType | where-object {$_.Name -eq "MpsSvc"} | Format-Table -auto

Get-Service BITS | Select StartType

Write-Host ($list | Where-Object {!($target -match $_)})

Arrays

Create an Empty Array

An empty array can be created by using @()
Example:

$data = @()
$data.count

$data = @('Zero','One','Two','Three')
$data.count

Accessing the items of the arrays

Example:

$data[0]
$data[1]
$data[2]

Using a special index

Example:

$data[0,2,3]

$data[1..3]

$data[-1]

$data.count

$date = Get-Date
$date.count

Updating the items of the arrays

Example:

$data[2] = 'dos'

$data[3] = 'tres'

For more information on Arrays this link

HashTables

Creating a HashTable

A hashtable is a data structure, much like an array, except you store each value (object) using a key. It's a basic key/value store. First, we create an empty hashtable.

Example:

$ageList = @{}

Notice that braces, instead of parentheses, are used to define a hashtable. Then we add an item using a key like this:

$key = 'Kevin'
$value = 36
$ageList.add( $key, $value )

$ageList.add( 'Alex', 9 )

Accessing the Elements using the brackets

$ageList['Kevin']
$ageList['Alex']

Creating Hashtables with values

$ageList = @{
    Kevin = 36
    Alex  = 9
}

The real value of this type of a hashtable is that you can use them as a lookup table.

Multiselection

$environments = @{
    Prod = 'SrvProd05'
    QA   = 'SrvQA02'
    Dev  = 'SrvDev12'
}

Iterating over our hashtables

GetEnumerator()

GetEnumerator() for iterating over our hashtable.

$ageList.GetEnumerator() | ForEach-Object{
    $message = '{0} is {1} years old!' -f $_.key, $_.value
    Write-Output $message
}

The enumerator gives you each key/value pair one after another. It was designed specifically for this use case.

For more information on the HashTables visit URL

Strings

Concatenation

$name = 'Kevin Marquette'
$message = 'Hello, ' + $name

Variable Substitution

$message = "Hello, $first $last.

Command substitution

$directory = Get-Item 'c:\windows'
$message = "Time: $directory.CreationTime"

You would be expecting to get the CreationTime off of the $directory, but instead you get this Time: c:\windows.CreationTime as your value. The reason is that this type of substitution only sees the base variable. It considers the period as part of the string so it stops resolving the value any deeper.
It just so happens that this object gives a string as a default value when placed into a string. Some objects give you the type name instead like System.Collections.Hashtable. Just something to watch for.
PowerShell allows you to do command execution inside the string with a special syntax. This allows us to get the properties of these objects and run any other command to get a value.

$directory = Get-Item 'C:\Windows'
$message = "$($directory.CreationTime)"
$message

Command Execution

You can run commands inside a string. Even though I have this option, I don't like it. It gets cluttered quickly and hard to debug. I either run the command and save to a variable or use a format string.

$message = "Date: $(Get-Date)"

Format String

$first = "first"
$last = "Answer"

$values = @(
    "Kevin"
    "Marquette"
)
'Hello, {0} {1}.' -f $values

Joining Strings

$servers = @(
    'server1'
    'server2'
    'server3'
)

$servers  -join ','

For more information on String visit this Link

For Output Forwarding and redirection use the following reference blogs by Microsoft:

Blog 1
Blog 2

JsonToCsv Script

Script

Retrieve the Status Code of an API call

Script