A Quick PowerShell Reference Pocketbook

As most of us already know that PowerShell is a new scripting language from Microsoft based on .NET framework. Microsoft and other vendors are heavily placing the scripting needs around PowerShell for administrative use. Specially starting Windows 2008 PowerShell has become an integral part of the Windows environment. Here is a quick reference from my studies of PowerShell language. Since I am already familiar with other programming and scripting languages, I used Dr. Tobias PowerShell E-book for quickly learning the syntax and semantics of PowerShell.

Here is a quick reference guide that I created for my self for future reference which I thought will also be helpful for others. Please remember this is just a quick reference for those who have some programming or scripting back ground.

You can download MS Word and PF versions from here:
Word - A Quick PowerShell Reference Pocketbook
PDF - A Quick PowerShell Reference Pocketbook

Statement Evaluation Order:

Parenthesis ( ) are always evaluated first

Automatic Unit Recognition:

Units like KB, MB, and GB can be used with numbers like 1MB + 2GB. Results are in bytes by default.

Windows Batch & Other Commands:

cmd /c command-name

use & to execute commands in quotes, i.e. & "c:\autoexec.bat"

To execute a program in current directory, prefix program name with \ i.e. .\editplus.exe . Unless the folder is on

the windows path $env:path

Add folder to path: $env:path += ";C:\programs\Windows NT\accessories"

Cmdlet Convention: Use the forms of verbs and nouns i.e. Get-Help

Add, Clear, Compare, Convert, Copy, Export, Format, Get, Group, Import, Measure, Move, New, Out, Read, Remove, Rename, Resolve, Restart, Resume, Select, Set, Sort, Split, Start, Stop, Suspend, Tee (Split up), Test, Trace, Update, Write.

Cmdlet Parameters:

Common Parameters i.e. ErrorAction, WhatIf

Named Parameters i.e. string, string[]

Switch Parameter i.e. boolean ($true,$false)

Positional Parameters i.e. Get-ChildItem -recurse, -name, c:\windows *.exe

Disable Parameters: Use -- or "-Parameter" (quotes) to disable parameter recognition

Variables:

Definition:

$syntax i.e. $company = “Axiom Dynamics Corp.”

Typeless i.e. $one = 1

${special variable} i.e. ${I am special} = “Special”

$assignment = value or “cmdlet Result”

Multiple inline assignments are supported i.e. $ten = $10 = 10

separate statements by ; i.e. $one=1;$two=2

$_ - this reference

Swap variable values:

$Value1 = 10; $Value2 = 20;

$Value1, $Value2 = $Value2, $Value1

$Value1

$Value2

Virtual drive is a variable

Write-Protected variables

"backtick" character ’

"." before the script file path to turn off restrictions on visibility

Scope modifiers are private, local, script, and global

Type: $variable.GetType()

Type safety: [oneoftypes] $variable where,

[oneoftypes]: [array], [bool], [byte],[char],[datetime], [decimal], [double], [guid], [hashtable], [int16], [int32], [int], [int64],, [long], [nullable], [psobject], [regex], [sbyte], [scriptblock], [single], [float], [string], [switch], [timespan], [type], [uint16], [uint32], [uint64], [xml]

Variable Options: "None","ReadOnly","Constant","Private","AllScope"

Variable Validation Classes: ValidateNotNullOrEmptyAttribute,ValidatePatternAttribute,ValidateRangeAttribute,ValidateSetAttribute

Operators:

Arithmetic:

Hex are prefixed with 0x

Operators: +, -, *, /, %

Conditional: -eq, -ceq, -ieq, -ne, -cne, -ine, -gt, -cgt, -igt, -ge, -cge, -ige, -lt, -clt, -ilt, -le, -cle, -ile, -contains, -ccontains, icontains, -notcontains, -cnotcontains, -inotcontains, -not/!, -and, -or, -xor

If/ElseIf/Else

Switch w/ default

strings (case sensitive)

wildcards

regex

expressions,

Arrays:

The comma always creates an array.

Verify e.g. $a is [Array]

Index starts at 0 and -1 is last element

Force to return array by using @()

Create New Array i.e.

$arr = 1..4

$arr = 1,2,3,4

$arr = "1","2"

$arr = 1

$arr = @()

Reverse Arrays

New elements Can be added by using += operator

Strongly Typed Arrays: [[int] ]$arr = 1,2,3

Arrays (returns matching / unlatching members)

Hash Tables:

Key-Value pair sep by ;

Access/Modify using either [] or .dot

Note: Arrays and HT are references to data

Pipeline:

Cmdlets To Pipe: Compare-Object, ConvertTo-Html, Export-Clixml,Export-Csv, ForEach-Object, Format-List, Format-Table, Format-Wide, Get-Unique, Group-Object, Import-Clixml, Measure-Object, more, Out-File, Out-Host, Out-Host, -paging, Out-Null (suppress output), Out-Printer, Out-String, Select-Object, Sort-Object, Tee-Object, Where-Object (?), Out-Default, Out-Host, * (wild card), Scriptblocks,

Modes: Sequential/Streaming Mode

ETS - Extended Type System: Emergency mode,

$$ - last token of pipeline

Loops:

ForEach-Object ("{indexes}") == %

ForEach - works with collection

Do/While, While, For, break, continue, :label

Aliases:

Example: PowerShell Virtual Drives

$alias: Get-PSDrive

dir alias:

- Group-Object definition

Create new aliases using Set-Alias, i.e. Set-Alias edit notepad.exe

Save Aliases using profiles or Export-Alias/Import-Alias cmdlets.

Life span of alias and function are only when PS console is open.

Functions:

Syntax: myFunc { commands/code $args }, multi line (enter) / single line (;

Calling: $function:tabexpansion | Out-File myscript.ps1/>file.ps1

Write-protected functions: Set-Item function:{//code} -option constant

Delete function: Del function:test,

Arguments: Args: $args - spaces ""

Parameters: function myFunc([type] $Param1=110, $Param2=$(Get-Date), [Switch] ParamN)

Returns are array or return keyword or omit returns

Write-Debug ,$ErrorActionPreference,

Stop-Process -nameofFunction

Dir function:

$function: prompt

Function {begin{}process{}end{}}

Object:

New-Object: Creates new object

Add-Member (NoteProperty, ScriptMethod, CodeMethod, Method)

Properties and Methods: $objectName.PropertyName or $objectName.MethodName()

Versioning: Major, Minor, Build and Revision

-static, constructors

Can load assemblies and COM.

Scripts & Other Language Integration:

Windows Batch Files

VBScript (Wscript //H:CScript - console, WScript //H:WScript – Windows)

.\filename.ext

Own: ps1.

Before executing scripted created on other machines you must Set-ExecutionPolicy to RemoteSigned

.\myscript.ps1

Get-ExecutionPolicy, Set-ExecutionPolicy RemoteSigned

md $env:appdata\PSScripts

\myscript.ps1 Tobias,

$($args[0])

param ($path, $name), param ([string] $Name=$( ` Throw "Parameter missing: -name Name")

[int]$age=$( `,. .\calcfunctions.ps1,

. $env:appdata\PSLib\calcfunctions.ps1,

{begin{} process{} end{}}

Four Different Profile Scripts: All users[private],Current user[private]

Debugging:

What-if

Confirm:Low, Medium, and High, $ConfirmPreference = "Low"

ErrorAction/$ErrorActionPreference:SilentlyContinue,Continue,Stop,Inquire

$?

Trap {}

$_.Exception.Message

ErrorVariable myError

$Error

Throw

Write-Debug, $DebugPreference:SilentlyContinue,Continue,Stop,Inquire, Set-PSDebug –step

@"

{index[,alignment][:format]}