Getting started with Powershell

Getting Started with PowerShell

• ·         Install power shell in your XP machine. In Windows 7 it is present by default. Download is available in the Microsoft Site. http://www.microsoft.com/download/en/details.aspx?id=7217
• ·         launch PowerShell in start -> run by typing powershell
• ·         Now let's a write our first script to modify the dates of the files present under the folder "C:\PowershellTest\testFiles" to current date and time plus 5 minutes on each file.
• ·         Create a txt file and rename to "MyFirstTest.ps1". Edit the file with the below code. It adds the current time to the first file and adds another 5 min to the each file.

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#  getting the current time

$Now= Get-Date

#   Listing the files and folders under the folder

$TargetFolder = Get-ChildItem "C:\PowershellTest\testFiles"

#   For loop , variable must be preceded with "$"

foreach($file in $Targetfolder)

{

$file.LastWriteTime = $Now

#  Adding 5 min

$Now = $now.Addminutes(5)

}

#  Displays output

$TargetFolder

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• ·         In PowerShell, ALL variable names must start with the "$" character
• ·         "#"is used for comments
• ·         You can debug the script using the powershell editor (powershell_ise.exe) which is already part of the application.
• ·         Open command prompt and type powershell.exe. It will open up a power shell window. The result would be as shown below.

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PS P:\> C:\Powershelltest\MyfirstTest.ps1

    Directory: C:\ PowershellTest\testfiles

Mode                LastWriteTime     Length Name

----                -------------     ------ ----

-a---         7/27/2011   8:26 AM          0 New Bitmap Image.bmp

-a---         7/27/2011   8:31 AM      12800 New Microsoft PowerPoint Presen ion.ppt

-a---         7/27/2011   8:36 AM      10752 New Microsoft Word Document.doc

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  First Issue:

File MyFirstTest.ps1cannot be loaded because the execution of scripts is disabled on this system. Please see "get-help about_signing"

Reason: The security setting does not allow you to execute a script, by default the Execution Policy is set to Restricted.  This is the so-called Execution Policy

There are 4 policy levels:

1.       Restricted: Individual cmdlets can run, but not saved Powershell scripts. This is the default setting.
2.       AllSigned: Scripts can run, but must have a digital signature even if written on the local computer. Prompts you before running scripts from trusted publishers.
3.       RemoteSigned: Scripts written on the local computer do not need a digital signature, but any script downloaded from outside (email, IM, Internet) must have a signature to execute.
4.       Unrestricted: Any script can run, but scripts downloaded from outside will run with a warning.

To change the Execution Policy to Unrestricted, type the following command in Powershell

Set-ExecutionPolicy Unrestricted