Powershell v2 Day 1


Class Notes Day 1

Get-Command -CommandType cmdlet | Where-Object { $_.Parameters.Keys -contains "ComputerName"}

$blah =Get-Command Test-WSMan


get-process | ? { $_.workingset64 -gt 100mb }

$ScriptBlock = { $_.workingset64 -gt 100mb }

get-process | ? $ScriptBlock

Running scripts

& run script in a child process no access to varibles in the script

. run script in current process variables will show in the shell.


-Expandable strings " "

-Literal strings  ' '

"blah" | gm

$blah = "blah"

$blah | gm

Get-EventLog -After (Get-Date 7/18/2011) -LogName application

THis one fails

Get-EventLog -After ($date=Get-Date 7/18/2011; $date) -LogName application

This one works

Get-EventLog -After $($date=Get-Date 7/18/2011; $date) -LogName application

These two lines are similar but different

invoke-expression "Get-process explorer"

& "Get-process explorer" -fails because of the space

Command and expression parsing modes

& puts you in command mode $ "Get-process"


$array = 1,2,3


#The next line returns the members of each of the items in the array

#the two lines following return the members of the array itself

$array | gm

Get-Member -InputObject $array

the "," tells powershell not to unwrap the object See , Comma operator in get-help about_Operators | less -i ,$array | gm

$array = @()

$array +=1

$array +=10


#Return an array if the data is not already an array (will not wrap an array in another array)

$proc = @( Get-Process explorer)

#increment or decrement ++ -- can be done pre and post







write-host ($a++)

write-host (++$a)

#bankers rounding (rounding to even)

[int32] 10.5

[int32] 11.5

name of class :: static method operator name of method


[system.math] | get-member -static

[Math]::Round(10.5, 0)

[Math]::Round(10.5, 2)

[Math]::Round(10.5, 0, "AwayFromZero")

[Math::Round([Math]::PI, 15)


[System.web.httputility]::HTMLDecode("Hello & goodbye")




Get-WmiObject -Class win32_service -ComputerName . -Filter "name='WinRM'"

Get-WmiObject -Class win32_service -ComputerName . -Filter "name=$ServiceName"

#Build filter first then

$filter = "name='$ServiceName'"

Get-WmiObject -Class win32_service -ComputerName . -Filter $filter

Get-WmiObject -Class win32_service -ComputerName . -Filter "name='$ServiceName'"

Get-WmiObject -List | ? { $_.__DERIVATION -contains '__Event'}

#Bitwise operators

File Attributes

A archive

D Director

S system

H hidden

R read only


00100000 Archive bitmask

cd c:\

gci -force

gci -force | ? {$_.Attributes -band 0x2} # Hidden

gci -force | ? {$_.Attributes -band 0x10} #Directory


gci -force | ? {$_.Attributes -band [System.IO.FileAttributes] "ReadOnly"}

gci | ? {$_.PSIsContainer}   # directory

gci | ? {!($_.PSIsContainer)} # not directory

Get-EventLog -LogName system | ? {$_.message -like "*shutdown*"}

"999-99-9999" -match "\d\d\d-\d\d-\d\d\d\d"

"999-99-9999" -match "\d{3}-\d{2}-\d{4}"

Hashtable = Associative array = dictionary


#Grep like




$env:path -split ";"

Import-Csv -Path C:\Windows\WindowsUpdate.log -Delimiter "`t" -Header "Date","Time","ThreadID","Eventid","Component","Message"

$logs=Import-Csv -Path C:\Windows\WindowsUpdate.log -Delimiter "`t" -Header "Date","Time","ThreadID","Eventid","Component","Message"


$logs | Group-Object -Property Component

Format Operator page 61


$errorString = "An error occured.`nMessage: {0}"

$errorString -f "Bad Stuff"

An error occured.

Message: Bad Stuff




Heading foo


PS Code Here blah