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? Perl The PowerShell language is similar to Perl. PowerShell includes ◦ more than 130 standard command line tools ◦ for functions that formerly required users VBVBScriptC#  to create scripts in VB, VBScript or C#.

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Cmdlet Windows PowerShell Cmdlet Cmdlet Cmdlet (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.NET ◦ 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-Process Can also be typed as:ps

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 Aliases PowerShell commands are usually long. ◦ example: Get-ChildItem. However, PowerShell has aliases. ◦ Example: ◦ “dir” is the same as “Get-ChildItem”get-alias 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 PowerShell Once 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: ps ps One very useful Cmdlet is ps ◦ or get-process lists 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 –descending

Sorting wrt Memory Usage

Filtering & Splitting the Commands User can filter that ◦ the “powershell” not to be seen in output  Add a filter piped Cmdlets can be ◦ split over multiple lines: ps | where-object –FilterScript {$_.processname -ne "powershell"} | sort-object WS –descending

Filtered

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

Displaying in Browser

Find all the processes on a computer that started today Get-Process | Where {$_.starttime -ge [datetime]::today}

Find the processes that use more than 1000 MB of memory and kill them get-process | where-object { $_.WS -gt 1000MB } | stop-process -whatif

Calculate the number of bytes in the files in a directory get-childitem | measure-object -property length -sum

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

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

Piped Commands dir | sort LastWriteTime | more

$a = dir | sort LastWriteTime PS C:\WINDOWS> $a = dir | sort LastWriteTime $a[0] PS C:\WINDOWS> $a[0] $a[1] PS C:\WINDOWS> $a[1]