MS WINDOWS POWER SHELL

CSE 535 Operating Systems

What is Power Shell

PowerShell is Microsoft Windows’ object-oriented programming language interactive command line shell

PowerShell designed to ◦ automate system tasks: such as batch processing

◦ create systems management tools ◦ for commonly implemented processes

What is it for?

The PowerShell language is similar to PerlPerl. PowerShell includes

◦more than 130 standard command line tools ◦ for functions that formerly required users

to create scripts in VBVB, VBScriptVBScript or C#C#.

Where to Download?

http://www.microsoft.com/downloads/details.aspx?FamilyID=50633a1f-a665-425d-923c-1a269f8ac084&displayLang=en

Windows PowerShell CmdletCmdlet

CmdletCmdlet (or Command-let) ◦which .NET objects can be accessed

from the command line. ◦A Cmdlet name consists of two elements:

a verb and a noun

Example: ◦one of the most useful Cmdlets:

Get-help

Automating Tasks PowerShell offers ways

◦ to automate tasks:

Cmdlets:◦ very small .NET classes ◦ appear as system commands

Scripts:◦ combinations of cmdlets and associated logic.

Executables:◦ standalone tools

Instantiation of standard .NET classes.

Integrating with .NET

PowerShell integrates with the .NET environment Can be embedded within other applications.

Over a hundred cmdlets are included to be used separately or combined with others

to automate more complex tasks Users can

also create and share cmdlets.

Abbreviations for Cmdlets

there are abbreviations ◦ for some of the Cmdlets, for example:

Get-ProcessGet-Process

Can also be typed as:

psps

Linux-similar Cmdlets

“ps” ◦ is command familiar to Linux users ◦ as the command

to view details about currently running processes.

there are a number of ◦ other Linux-PowerShell parallels:

“man” is the same as “Get-Help –detailed”“ls” is the same as “Get-ChildItem”“pwd” is the same as “Get-Location”

Understanding AliasesPowerShell commands are usually long.

◦example: Get-ChildItem. However, PowerShell has aliases.

◦Example:◦ “dir” is the same as “Get-ChildItem”

get-alias get-alias

get-alias dir get-alias dir

Obtaining PowerShell

PowerShell is installed in Windows Server 2008 is also part of Windows 7,

it does not come ready loaded with XP or Vista!

Running PowerShellOnce PowerShell has been installed

◦ then it can be run in two ways:

Click on “Start”, “Run” ◦and then type in “powershell”

Start a new command prompt ◦and then type in “powershell”

the user can start using ◦ the PowerShell commands.

Cmdl: psOne very useful Cmdlet is psps

◦or get-processlists the currently running processes

◦ the number of memory page (frame)s◦ the percentage of processor usage

Pipe and Sort

The list is sorted alphabetically ◦according to the process name.

You can sort WS field ◦According to the memory usage

To do this the user ◦ “pipes” the output of ps ◦ to a second Cmdlet “sort-object”

ps | sort-object WS –descendingps | sort-object WS –descending

Sorting wrt Memory Usage

Filtering & Splitting the Commands

User can filter that◦ the “powershell” not to be seen in output

Add a filterpiped Cmdlets can be

◦split over multiple lines:

ps |ps | where-object –FilterScriptwhere-object –FilterScript{$_.processname -ne "powershell"} {$_.processname -ne "powershell"} || sort-object WS –descendingsort-object WS –descending

Filtered

To concatenation symbolThe concatenation symbol (>)

◦ will send the result output file ◦ after the information has been converted to HTML ◦ so that it can then be viewed in a web browser:

ps |ps |where-object -FilterScript where-object -FilterScript {$_.processname -ne "powershell"} |{$_.processname -ne "powershell"} |sort-object WS –descending |sort-object WS –descending |convertto-html -property Name,convertto-html -property Name,WS > ps.htmlWS > ps.html

Displaying in Browser

Find all the processes on a computer that started today

Get-Process | Where {$_.starttime -ge Get-Process | Where {$_.starttime -ge [datetime]::today}[datetime]::today}

Find the processes that use more than 1000 MB of memory and kill them

get-process | where-object { $_.WS -gt get-process | where-object { $_.WS -gt 1000MB } | stop-process -whatif 1000MB } | stop-process -whatif

Calculate the number of bytes in the files in a directory

get-childitem | measure-object -property get-childitem | measure-object -property length -sum length -sum

Defining Variables

PS C:\> $a = 5 $a = 5

PS C:\> $a $a

5

PS C:\>

Determine Variable

PS C:\> $a.GetType() $a.GetType()

Piped Commands

dir | sort LastWriteTime | moredir | sort LastWriteTime | more

PS C:\WINDOWS> $a = dir | sort $a = dir | sort LastWriteTimeLastWriteTime

PS C:\WINDOWS> $a[0] $a[0]

PS C:\WINDOWS> $a[1] $a[1]