IntroToPowershellPresentation.ps1.md

<#
   ____                        ____  _          _ _ 
  |  _ \ _____      _____ _ __/ ___|| |__   ___| | |
  | |_) / _ \ \ /\ / / _ \ '__\___ \| '_ \ / _ \ | |
  |  __/ (_) \ V  V /  __/ |   ___) | | | |  __/ | |
  |_|   \___/ \_/\_/ \___|_|  |____/|_| |_|\___|_|_|

A crash course in the shell power of PowerShell

#>

# pay no attn to the below goop (this should help me track my progress during the talk)
$groupName = 'TODO Fill this in!!!'
. .\TimeTracker.ps1
Start-TrackingTime 65 # <-- how long is this talk?
<#

Who am I?

Jason Jarrett

• Twitter: @staxmanade
• Blog: http://elegantcode.com
• Some Code: http://github.com/staxmanade
• Employer: Vertigo

Some cool months of the year!

 J.A.S.O.N.
   J - July
   A - August
   S - September
   O - October
   N - November

#>

HowsMyTime "yourself"

<#

Enough about me! What about you?

• How many have ever used powershell?
• Programming experience:
  • More than 10 years?
  • Between 5-10 years?
  • Between 3-5 years?
  • Less than 3 years?
• Who has any amount of background in the Microsoft .Net space?

Goals for the talk:

• First a little background and fluffy stuff
• Language intro/overview
• Runtime Environment intro/overview
• Tips/Tricks
• Fun Stuff

Overview

What is it?

Windows PowerShell AKA (Windows Management Framework)

PowerShell is a dynamically typed scripting language composed of 2 major components

• Language
• Runtime environment

Brief history

• Command.com or cmd.exe
• Monad Manifesto (August 2002)
• First demoed at (PDC 2003)
• V 1.0 (November 2006)
• V 2.0 (August 2009)
• V 3.0 (Last quarter of 2012)

Where can I use it?

• V2.0 comes pre-installed on systems >= Win7 and Server 2008 R2
• V2.0 can be installed on windows going all the way back to Windows XP
• OSS linux ports out there that run on top of the Mono framework

Why should I care about it?

• Automate your daily mundane
• Prototype against .Net framework classes w/out having to File -> New -> Console Project
• If you know .net you are almost there

    #>

     HowsMyTime "powershell overview"

    <#

PowerShell Language/Syntax

Comments

# <--- to comment out a line

<#
    Comment out a block of stuff
    
    This whole presentation is littered with them :) !!!!
#>

Variable Declaration

$v1 = 1
echo $v1

$v2 = $v1 + 1;
echo $v2

# explicitly define it's data type
[int] $num1 = 1
echo $num1

# Notice how the .2 gets rounded as it converts it to an integer
[int] $num2 = 1.2 
echo $num2

[decimal] $num3 = 1.2
echo $num3

Arrays

$v3 = @( 1, 2, 3 )
echo $v3

# Working with Arrays

# Concat 2 arrays
@(1,2,3) + @('a', 'b', 'c') + @(4,5,6)

# Different ways to add to an array.
$a1 = @(1,2,3); $a1
$a1 += 4; $a1
$a1 += 5; $a1
$a1 += 6; $a1

$a1 += @(7,8,9); $a1

# Can't remove from the array.  You'd have to create a new array with just the items you wanted. (Or use a .net class to do it list)
$a1 -= 7

Hash table

$v3 = @{
    "name1" = "value1";
    "name2" = "value2"; 
    "name3" = "value3"; 
}

Read a value

$v3["name1"]

$v3.name1

Set a value

$v3.HelloKey = "Hello Value"

$v3["HelloKey"] = "Hello Something else"

$v3.HelloKey

Strings

'Hello World!' 
# or
"Hello World!"

Multiline strings

@'
Hello
World
'@

Note - these won't work

@'Hello
World
'@

@'
Hello
World'@

String Interpolation

Single quotes don't interpolate

'Hello $groupName' 

Double quotes DO interpolate

"Hello $groupName"

Wrap $(...) around expression within an string

"groupName variable is of type: $($groupName.GetType().FullName)"
"2 + 1564 = $(2 + 1564)"
"Current DateTime is = $(get-date)"
"Current DateTime is = $([System.DateTime]::Now)"

Escape characters with the ` (back-tick)

"Escape a quotation `"This is quoted`"."

sometimes you can just change the quote type used.

'Escape a quotation "This is quoted".'
"Escape a quotation `"$(get-date)`""
'Mix single and double quotes "$(get-date)".'    # <-- notice the single quote - no interpolation

Comparison operators

Are case-insensitive by default

    1 -eq 1 # equal
    1 -ne 0 # not equal 
    1 -gt 0 # greater than
    1 -ge 1 # greater than or equal
    1 -lt 4 # less than
    1 -le 1 # less than or equal
    
    "something" -like "*ethin*"                                  # Wildcard comparison
    "something" -notlike "*gni*"                                 # Wildcard comparison
    "This $groupName is boring!" -replace 'boring', 'AWESOME'    # Replace operator
    @(1,2,3) -contains 1                                         # Containment operator
    @(1,2,3) -notcontains 0                                      # Containment operator

Case-sensitive - put a c in front of each operator.

    # EX: -eq becomes -ceq (Case sensitive equal to)
    "aBc" -ceq "ABC" # (nope)

Regex

    "Welcome to the $groupName" -match "Welcome (.*)"            # Regular expression comparison
    $matches
    "Welcome to the $groupName" -notmatch "Welcome (.*)"         # Regular expression comparison
    $matches

Some other bits

    !$true              # Not $true
    (-not $true)        # Not $true
    $true -and $true    # And
    $false -or $true    # Or

General Syntax

if block

if( $true -or $false -or 1 -or "hi") {
    $true
}

if elseif else block

$v1 = 'c'
if( $v1 ) {
    "a"
} elseif( $v1 ) {
    "b"
} elseif( $v1 ) {
    "c"
} else {
    "d"
}

while loop

$v1 = 10
while( $v1 -gt 0 ) {
    $v1--
    echo $v1
}

do while loop

$v1 = 10
do {
    $v1--
    $v1
} while ( $v1 -gt 0 )

for loop

for($i = 0; $i -lt 10; $i++) {
    "$i"
}

foreach

$files = ls
foreach($file in $files) {
    "{0,10} bytes" -f $file.Length
}

switch

$v1 = "hi"
switch($v1) {
    "hello" { "no" }
    "world" { "no" }
    "hi"    { "yes" }
    default { "no" }
}

###try/catch/finally

try {
    throw "Oh SNAP!"
} catch {
    $_ 
}
finally{
    "Do some Cleanup"
}

Pipelines

# unlike *nix pipeline the output of the operation is not text but an object

ls | Get-Member

ls | where { $_.Extension -eq ".ps1" } | Sort-Object Length -Descending

$output = (ls | where { $_.Extension -eq ".ps1" } | Sort-Object Length -Descending)
$output.GetType()
$output[0].GetType()

Range operator

1..15

[char]'A'..[char]'z' | %{ [char]$_ }

1..15 | foreach{ "I can count to $_" }

4 kinds of commands powershell can execute

Cmdlets (pronounced command-lets)

Get-ChildItem

Script files (*.ps1 extension)

./HelloFromAScript.ps1

Functions

function HelloFromAFunction()
{
    echo "Hello World!"
}

HelloFromAFunction # Execute the above defined function


function OneParamApproach($param1, $param2)
{
    echo "$param1 - $param2"
}

OneParamApproach "Placing the params within the parentheses is one approach"


# same as above example for 2 parameters
function AnotherParamApproach()
{
    [param](
        $param1,
        $param2
    )

    echo "$param1 - $param2"
}

OneParamApproach "Placing the params within the parentheses is one approach"


# function that supports the pipeline.
function Add-Them-Up {
    BEGIN {
        # one time (at the beginning) setup code
        $total = 0
    }
    PROCESS {
        # grab the current item
        $currentItem = $_

        # do something with the item
        $total += $currentItem
    }
    END {
        # one time (at the end) teardown code
        $total
        }
}

@(1,2,3) | Add-Them-Up
1..100 | Add-Them-Up

plain ol executables

# already in your environment's "PATH"
    ipconfig.exe
    where.exe ipconfig
    where.exe powershell

# by specifying full path
    C:\Windows\System32\ipconfig.exe

# execute a command who's path was stored in a variable
    $cmd = 'C:\Windows\System32\ipconfig.exe'
    & $cmd /?

# same as above (without the variable)
    C:\Windows\System32\ipconfig.exe /?

Interact with the .Net framework

new up a .net object given a set of arguments to pass to the constructor

#    ctor of - DateTime(int year, int month, int day)
$JanFirst2009 = New-Object System.DateTime @(2009, 1, 1)
$JanFirst2009

$JanFirst2009.GetType()

calling methods on an object

(notice how calling .net function is different than powershell function (use of parenthases)

$JanFirst2009.AddDays(1)

Call a static property

[System.DateTime]::Now

Execute a static function

[System.String]::Format("Hello {0}!", $groupName)

Wire up to a .net event object. (This is really a PITA)

TODO: check the PS 3 to see if this got better

    $timer = New-Object Timers.Timer
    $timer.Interval = 1000
    $timer.Start()
    $job = Register-ObjectEvent -inputObject $timer -eventName Elapsed `
           -sourceIdentifier Timer.Random `
           -Action { Get-Random -Min 0 -Max 100;}

    Receive-Job $job
    $timer.Stop();
    Unregister-Event Timer.Random

XML

$someXml = [xml]'
<root>
    <person id="1002854">
        <firstName>Jason</firstName>
        <lastName>Jarrett</lastName>
    </person>
    <person id="532486">
        <firstName>Jesse</firstName>
        <lastName>Anderson</lastName>
    </person>
</root>'

$someXml
$someXml.GetType()

$someXml.root
$someXml.root.GetType()

$someXml.root.person[0]
$someXml.root.person[0].GetType()

$someXml.root.person[0].firstname
$someXml.root.person[0].firstname.GetType()

$someXml.root.person[0].id


foreach($person in $someXml.root.person){
    $person.lastName
}


$someXml.root.person | where { $_.id -eq 1002854 }

HowsMyTime "the powershell language"

PowerShell Runtime Environment

<#    

Tools

Tools for composing and executing PowerShell

- Powershell Console (Built-in)
- Powershell ISE (Built-in)
- PowerGUI (3rd party)
- others? (probably)

Great tools that leverage powershell or help you with powershell

- Chocolatey
- cinst wincommandpaste

#>    

Drives

The usual drives ("hard drives")

cd C:\
ls \\SomeNetworkShare\Folder\file.txt

get a list of all the drive providers

Get-PSDrive

'mount' a new folder as a namded drive.

# Note this is not a system/wide change, but the current powershell environment
New-PSDrive -PSProvider filesystem -Root C:\Code\ -Name Code

Variable drive

ls variable: | measure
$someNewRandomVar = 1
ls variable: | measure

Registry

Push-Location

#open regedit
regedit


cd HKCU:\
ls
cd HKCU:\Software
ls

# create a registry folder
mkdir JasonJ
cd .\JasonJ

Set-ItemProperty . newproperty "mynewvalue"

Pop-Location


rmdir HKCU:\Software\JasonJ -Force

Some other drive providers

# - Sql Server
# - Active Directory
# - build your own?

Aliases

#   Many of the commands you may know from dos or linux scripting work in PowerShell - accomplished by aliases
#   (map commands to shortcuts)

Print all alises

alias

Show what the underlying command is for dir and ls

alias dir
alias ls

Create your own aliases

# alias foo to the Get-ChildItem cmdlet

set-alias foo Get-ChildItem 

foo

Profile

$Profile is a global variable that describes where the current environment can load a profile script

$Profile

When you first start up - it ($profile) won't exist, but the path is specified

# 1. Create the directory
# 2. Create the file
# 3. Customize it for your own needs

# what is in the current profile?
cat $Profile

notepad $profile

Different environment specify different paths depending on the runtime/editor

# Powershell Console
# Powershell ISE
# The NuGet Package Manager Console (inside Visual Studio) uses different path

Execution Environment

Get-ExecutionPolicy

Set-ExecutionPolicy -ExecutionPolicy Restricted

<#
    Restricted - No scripts can be run. Windows PowerShell can be used only in interactive mode.

    AllSigned - Only scripts signed by a trusted publisher can be run.

    RemoteSigned - Downloaded scripts must be signed by a trusted publisher before they can be run.

    Unrestricted - No restrictions; all Windows PowerShell scripts can be run.
#>

Commandlets and common parameters

get-help about_CommonParameters

# WhatIf
mkdir temp
cd .\temp
1..10 | %{ new-item -Name "$_.txt" -type file }
rm *.txt -WhatIf
ls
rm *.txt
ls

# ErrorAction
rm This_file_doesnt_exist_on_disk.txt
rm This_file_doesnt_exist_on_disk.txt -ErrorAction silentlycontinue

HowsMyTime "the powershell runtime environment"

Usefull tips/tricks

Dot-sourcing a file (EX: see the TimeTracker.ps1 at the top of this file)

. .\SomeExternalScript.ps1
# Now I can access functions/variables the external script contains

II (Invoke-Item)

# open windows explorer at the current directory
ii .

ii http://google.com # <-- I wish this worked - might write my own a wrapper?

Pipe output to the clipboard

"Hello $groupName" | clip

cat README.md | clip

Get-Help

Get-Help
Get-Help ls
Get-Help alias

Show-Command

Show-Command ls

Get-History

Get-History

Start a powershell process as administrator

Start-Process PowerShell -Verb RunAs

Stop executing on error

By default powershell does not stop executing a script on error. When developing build scripts set:

$ErrorActionPreference = "stop";

Check command return codes

msbuild.exe mySolution.sln
if($LASTEXITCODE -ne 0) { throw "build error" }

Out-GridView

ls | out-gridview

Download and parse some XML

([xml] (new-object net.webclient).downloadstring('http://feeds.feedburner.com/ElegantCode')) | %{ $_.rss.channel.Item } | select title, creator

Progress Bar

1..100 | foreach{ 
    Write-Progress -activity "Sample progress bar" -PercentComplete $_;
    sleep -Milliseconds 20
}

Some special number shortcuts

1kb   # ==> kilo-byte 1024
1mb   # ==> mega-byte 1048576
1gb   # ==> giga-byte 1073741824
1tb   # ==> tera-byte 1099511627776
1pb   # ==> peta-byte 11258999068426240  11,258,999,068,426,240

#1eb   # ==> exa-byte ERR: does not work (but why would you need something that big?)
#1zb   # ==> zetta-byte ERR: wat?
#1yb   # ==> yotta-byte ERR: really?

note you don't have to use 1*b (ex: 1kb) you can specify any number (213kb ==> 218112)

Dig into my development environment setup script?

set-executionpolicy unrestricted;

iex ((new-object net.webclient).DownloadString('https://raw.github.com/staxmanade/DevMachineSetup/master/Bootstrap/BootIt.ps1'))

# Of particular interest
# - CD override
# http://elegantcode.com/2012/11/01/more-than-slightly-modified-cd-command-for-powershell/    

HowsMyTime "so-called useful stuff"

What is this?

# http://elegantcode.com/2011/08/30/powershell-text-to-speech-and-fun-with-a-4yr-old/
# case internet is down
function Start-The-Fun()
{
    $voice = new-object -com SAPI.SpVoice;

    while($true)
    {
	    write-host "->" -NoNewLine;
	    $msg = read-host;
	    $Voice.Speak( $msg, 1 ) | out-null;
    }
}

I promise to only do this (whever I feel it!) :)

iex (New-Object Net.WebClient).DownloadString("http://bit.ly/e0Mw9w")

HowsMyTime "done"

<#

This Presentation can be found at

http://github.com/staxmanade/PowershellPresentation

Jason Jarrett

• Twitter: @staxmanade
• Blog: http://elegantcode.com
• Some Code: http://github.com/staxmanade
• Employer: Vertigo

Thanks for listening...

   ____                        ____  _          _ _ 
  |  _ \ _____      _____ _ __/ ___|| |__   ___| | |
  | |_) / _ \ \ /\ / / _ \ '__\___ \| '_ \ / _ \ | |
  |  __/ (_) \ V  V /  __/ |   ___) | | | |  __/ | |
  |_|   \___/ \_/\_/ \___|_|  |____/|_| |_|\___|_|_|
 
#>