PowerShell
Basics
Get-Command # Retrieves a list of all the commands available to PowerShell
# (native binaries in $env:PATH + cmdlets / functions from PowerShell modules)
Get-Command -Module Microsoft* # Retrieves a list of all the PowerShell commands exported from modules named Microsoft*
Get-Command -Name *item # Retrieves a list of all commands (native binaries + PowerShell commands) ending in "item"
Get-Help # Get all help topics
Get-Help -Name about_Variables # Get help for a specific about_* topic (aka. man page)
Get-Help -Name Get-Command # Get help for a specific PowerShell function
Get-Help -Name Get-Command -Parameter Module # Get help for a specific parameter on a specific command
Operators
$a = 2 # Basic variable assignment operator
$a += 1 # Incremental assignment operator
$a -= 1 # Decrement assignment operator
$a -eq 0 # Equality comparison operator
$a -ne 5 # Not-equal comparison operator
$a -gt 2 # Greater than comparison operator
$a -lt 3 # Less than comparison operator
$FirstName = 'Trevor'
$FirstName -like 'T*' # Perform string comparison using the -like operator, which supports the wildcard (*) character. Returns $true
$BaconIsYummy = $true
$FoodToEat = $BaconIsYummy ? 'bacon' : 'beets' # Sets the $FoodToEat variable to 'bacon' using the ternary operator
Regular Expressions
'Trevor' -match '^T\w*' # Perform a regular expression match against a string value. # Returns $true and populates $matches variable
$matches[0] # Returns 'Trevor', based on the above match
@('Trevor', 'Billy', 'Bobby') -match '^B' # Perform a regular expression match against an array of string values. Returns Billy, Bobby
$regex = [regex]'(\w{3,8})'
$regex.Matches('Trevor Bobby Dillon Joe Jacob').Value # Find multiple matches against a singleton string value.
Flow Control
if (1 -eq 1) { } # Do something if 1 is equal to 1
do { 'hi' } while ($false) # Loop while a condition is true (always executes at least once)
while ($false) { 'hi' } # While loops are not guaranteed to run at least once
while ($true) { } # Do something indefinitely
while ($true) { if (1 -eq 1) { break } } # Break out of an infinite while loop conditionally
for ($i = 0; $i -le 10; $i++) { Write-Host $i } # Iterate using a for..loop
foreach ($item in (Get-Process)) { } # Iterate over items in an array
switch ('test') { 'test' { 'matched'; break } } # Use the switch statement to perform actions based on conditions. Returns string 'matched'
switch -regex (@('Trevor', 'Daniel', 'Bobby')) { # Use the switch statement with regular expressions to match inputs
'o' { $PSItem; break } # NOTE: $PSItem or $_ refers to the "current" item being matched in the array
}
switch -regex (@('Trevor', 'Daniel', 'Bobby')) { # Switch statement omitting the break statement. Inputs can be matched multiple times, in this scenario.
'e' { $PSItem }
'r' { $PSItem }
}
Variables
$a = 0 # Initialize a variable
[int] $a = 'Trevor' # Initialize a variable, with the specified type (throws an exception)
[string] $a = 'Trevor' # Initialize a variable, with the specified type (doesn't throw an exception)
Get-Command -Name *varia* # Get a list of commands related to variable management
Get-Variable # Get an array of objects, representing the variables in the current and parent scopes
Get-Variable | ? { $PSItem.Options -contains 'constant' } # Get variables with the "Constant" option set
Get-Variable | ? { $PSItem.Options -contains 'readonly' } # Get variables with the "ReadOnly" option set
New-Variable -Name FirstName -Value Trevor
New-Variable FirstName -Value Trevor -Option Constant # Create a constant variable, that can only be removed by restarting PowerShell
New-Variable FirstName -Value Trevor -Option ReadOnly # Create a variable that can only be removed by specifying the -Force parameter on Remove-Variable
Remove-Variable -Name firstname # Remove a variable, with the specified name
Remove-Variable -Name firstname -Force # Remove a variable, with the specified name, that has the "ReadOnly" option set
Functions
function add ($a, $b) { $a + $b } # A basic PowerShell function
function Do-Something { # A PowerShell Advanced Function, with all three blocks declared: BEGIN, PROCESS, END
[CmdletBinding]()]
param ()
begin { }
process { }
end { }
}
Working with Modules
Get-Command -Name *module* -Module mic*core # Which commands can I use to work with modules?
Get-Module -ListAvailable # Show me all of the modules installed on my system (controlled by $env:PSModulePath)
Get-Module # Show me all of the modules imported into the current session
$PSModuleAutoLoadingPreference = 0 # Disable auto-loading of installed PowerShell modules, when a command is invoked
Import-Module -Name NameIT # Explicitly import a module, from the specified filesystem path or name (must be present in $env:PSModulePath)
Remove-Module -Name NameIT # Remove a module from the scope of the current PowerShell session
New-ModuleManifest # Helper function to create a new module manifest. You can create it by hand instead.
New-Module -Name trevor -ScriptBlock { # Create an in-memory PowerShell module (advanced users)
function Add($a,$b) { $a + $b } }
New-Module -Name trevor -ScriptBlock { # Create an in-memory PowerShell module, and make it visible to Get-Module (advanced users)
function Add($a,$b) { $a + $b } } | Import-Module
Module Management
Get-Command -Module PowerShellGet # Explore commands to manage PowerShell modules
Find-Module -Tag cloud # Find modules in the PowerShell Gallery with a "cloud" tag
Find-Module -Name ps* # Find modules in the PowerShell Gallery whose name starts with "PS"
Install-Module -Name NameIT -Scope CurrentUser -Force # Install a module to your personal directory (non-admin)
Install-Module -Name NameIT -Force # Install a module to your personal directory (admin / root)
Install-Module -Name NameIT -RequiredVersion 1.9.0 # Install a specific version of a module
Uninstall-Module -Name NameIT # Uninstall module called "NameIT", only if it was installed via Install-Module
Register-PSRepository -Name <repo> -SourceLocation <uri> # Configure a private PowerShell module registry
Unregister-PSRepository -Name <repo> # Deregister a PowerShell Repository
Filesystem
New-Item -Path c:\test -ItemType Directory # Create a directory
mkdir c:\test2 # Create a directory (short-hand)
New-Item -Path c:\test\myrecipes.txt # Create an empty file
Set-Content -Path c:\test.txt -Value '' # Create an empty file
[System.IO.File]::WriteAllText('testing.txt', '') # Create an empty file using .NET Base Class Library
Remove-Item -Path testing.txt # Delete a file
[System.IO.File]::Delete('testing.txt') # Delete a file using .NET Base Class Library
Hashtables (Dictionary)
$Person = @{
FirstName = 'Trevor'
LastName = 'Sullivan'
Likes = @(
'Bacon',
'Beer',
'Software'
)
} # Create a PowerShell HashTable
$Person.FirstName # Retrieve an item from a HashTable
$Person.Likes[-1] # Returns the last item in the "Likes" array, in the $Person HashTable (software)
$Person.Age = 50 # Add a new property to a HashTable
Windows Management Instrumentation (WMI) (Windows only)
Get-CimInstance -ClassName Win32_BIOS # Retrieve BIOS information
Get-CimInstance -ClassName Win32_DiskDrive # Retrieve information about locally connected physical disk devices
Get-CimInstance -ClassName Win32_PhysicalMemory # Retrieve information about install physical memory (RAM)
Get-CimInstance -ClassName Win32_NetworkAdapter # Retrieve information about installed network adapters (physical + virtual)
Get-CimInstance -ClassName Win32_VideoController # Retrieve information about installed graphics / video card (GPU)
Get-CimClass -Namespace root\cimv2 # Explore the various WMI classes available in the root\cimv2 namespace
Get-CimInstance -Namespace root -ClassName __NAMESPACE # Explore the child WMI namespaces underneath the root\cimv2 namespace
Asynchronous Event Registration
Register for filesystem events
$Watcher = [System.IO.FileSystemWatcher]::new('c:\tmp')
Register-ObjectEvent -InputObject $Watcher -EventName Created -Action {
Write-Host -Object 'New file created!!!'
}
Perform a task on a timer (ie. every 5000 milliseconds)
$Timer = [System.Timers.Timer]::new(5000)
Register-ObjectEvent -InputObject $Timer -EventName Elapsed -Action {
Write-Host -ForegroundColor Blue -Object 'Timer elapsed! Doing some work.'
}
$Timer.Start()
PowerShell Drives (PSDrives)
Get-PSDrive # List all the PSDrives on the system
New-PSDrive -Name videos -PSProvider Filesystem -Root x:\data\content\videos # Create a new PSDrive that points to a filesystem location
New-PSDrive -Name h -PSProvider FileSystem -Root '\\storage\h$\data' -Persist # Create a persistent mount on a drive letter, visible in Windows Explorer
Set-Location -Path videos: # Switch into PSDrive context
Remove-PSDrive -Name xyz # Delete a PSDrive
Data Management
Get-Process | Group-Object -Property Name # Group objects by property name
Get-Process | Sort-Object -Property Id # Sort objects by a given property name
Get-Process | Where-Object -FilterScript { $PSItem.Name -match '^c' } # Filter objects based on a property matching a value
gps | where Name -match '^c' # Abbreviated form of the previous statement