List current functions in powershell

You can use the following command to display what functions that are part of your current shell.

Get-ChildItem function:*

To view the code contained in a function - in this example the function "mkdir":

$function:mkdir

If you would like to change a function, simply create a new function of the same name:

function C: {
    Write-Host "You are not allowed on drive C: !"
    Set-Location M:
}

The function TabExpansion is called to generate the list of possible completion matches when using the TAB key.
The function prompt determines what your command prompt looks like (se earlier post) .

Configuring PowerShell

Enable scripts - in order to execute script in PowerShell, the default Executionpolicy of "Restricted", has to be changed to "Unrestricted":

Set-Executionpolicy Unrestricted

Instead of "Unrestricted" you could also selec RemoteSigned, AllSigned, Restricted, Default (to reset to the PowerShell default)

Configure my profile
Determine where my profile is stored through the following default variable:

$profile

Edit it by using

notepad $profile

To create the file first:

new-item -path $profile -itemtype file -force

# Set Aliases
set-alias n notepad

# Set Prompt
function prompt
{
$nbsp;$nbsp;$nbsp;$nbsp;Write-Host ("--< " + $(Get-Location) + " >--< " + $(Get-Date) + " >--") -foregroundcolor DarkRed
$nbsp;$nbsp;$nbsp;$nbsp;Write-Host "PS>" -nonewline -foregroundcolor Cyan
$nbsp;$nbsp;$nbsp;$nbsp;return " "
}

• %UserProfile%\My Documents\WindowsPowerShell\profile.ps1 - This profile applies only to the to the current user, but affects all shells.
• %UserProfile%\\My Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1 - This profile applies only to the current user and the Microsoft.PowerShell shell.
• %windir%\system32\WindowsPowerShell\v1.0\profile.ps1 - This profile applies to all users and all shells.
• %windir%\system32\WindowsPowerShell\v1.0\ Microsoft.PowerShell_profile.ps1 - This profile applies to all users, but only to the Microsoft.PowerShell shell.

Read more about it all here.

How much RAM have I got?

A small function to retrieve the number and size of RAM modules in a PC

function GetMem{
    $a = Get-WmiObject win32_physicalmemory -computername $args[0]
    Write-Host ("-" * 60)`n "Memory Configuration of" $args[0] `n("-" * 60)
    foreach ($b in $a) {
        Write-Host $b.tag `t $b.capacity "bytes" `t ($b.capacity/1mb) "mb"
    }
}

Usage:

GetMem

Useful .NET stuff

One of the big advantages of PowerShell is the easy access to .NET
For instance, in order to gain access to the .NET functionality contained in datatime we
can use Get-Member to look at the available methods:

$a = [datetime]
Get-Member -InputObject $a -s

Or written in a shorter notation:

[datetime] | gm -s

We might find the IsLeapYear or Parse methods interisting, and decide to try them out:

[datetime]::Parse("2008/02/29 012:23:45")

What? January 29th? Maybe 2008 is a leapyear? Try this:

[datetime]::IsLeapYear(2008)

Another interesting part of .NET might be math . Lets use it to round the number 9876.54321 to one decimal:

[math]::round(9876.54321,1)

Other interesting uses for .NET:

[datetime]::now.addminutes(-1000000) #give me datetime 1 million minutes ago)
[console]::title = "My PoweShell window" #sets the title of the current console window

Memory consumption

Here are two small script used for displaying the name of currently running processes, as well as the amount of memory currently allocated (through VMM) to Virtual Machines (either Microsoft Virtual PC or Virtual Server):

function GetMem {
    $processes = Get-WmiObject win32_process | Sort-Object -property WorkingSetSize -descending
    $processes | format-table `
         ProcessName, `
         Handle, `
         WorkingSetSize, `
         @{label="in MB"; Expression={([Math]::round($_.WorkingSetSize / 1mb,1))}} `
         -autosize
    $TotalMem= 0
    foreach ($process in $processes) {
         $TotalMem = $TotalMem + $process.WorkingSetSize
    }
    $TotalMem_in_MB = [math]::round($TotalMem/1mb,1)
    Write-Output "`tTotal mem used: `t $TotalMem ($TotalMem_in_MB MB)`n"
}

$a = GetMem; $a

function GetVMmem {
    $virtualmachines = Get-WmiObject virtualmachine -namespace "root\vm\virtualserver"
    $virtualmachines | format-table `
         @{label="ProcessName"; Expression={("VirtualMachine " + $_.Name)}}, `
         PhysicalMemoryAllocated, `
         @{label="in MB"; Expression={([Math]::round($_.PhysicalMemoryAllocated/1mb,1))}} `
         -autosize
    $TotalMem = 0
    foreach ($virtualmachine in $virtualmachines) {
         $TotalMem = $TotalMem + $virtualmachine.PhysicalMemoryAllocated
    }
    $TotalMem_in_MB = [math]::round($TotalMem/1mb,1)
    Write-Output "`tTotal mem used: `t $TotalMem ($TotalMem_in_MB MB)`n"
}

$b = GetVMmem; $b

Environment variables

To use the standard windows environment variables (temp, computername, windir, etc.) in PowerShell, you can use the following notation:

${env:temp}

Or, if the full names (not 8.3 DOS notation) are required:

[io.path]::GetFullPath($env:temp)

Note that if $env:path is needed, you have to use the first notation (which in this case returns the full path/file names).

${env:path}

[io.path]::GetFullPath($env:path) ## Won't work, as the returned value is too large.

Sending emails from powershell

Here is a small script to send emails from PowerShell. Remember to use a valid SMTP server.

$SMTPserver = "mysmtp.nowhere.now"
$fileattachment = "c:\\boot.ini"
$from = "hans@nowhere.now"
$to = "somebody@somewhere.org"
$subject = "PowerShell Test"
$emailbody = "this is my very first email send through PowerShell 1.0"

$mailer = new-object Net.Mail.SMTPclient($SMTPserver)
$msg = new-object Net.Mail.MailMessage($from, $to, $subject, $emailbody)
$attachment = new-object Net.Mail.Attachment($fileattachment)
$msg.attachments.add($attachment)
$mailer.send($msg)

PowerShell can be strict

Normally PowerShell silently ignores the use of uninitialized variables.
For instance, the script below will simply assume that $b has no value, and return the value "5"

$a = 5
$a + $b

It is often useful to force PowerShell to return an error if an unitialized variable is used.
This can be accomplished by enabling "strict" mode:

Set-PSDebug -strict

If the earlier scritp is run again an error is returned:

$a = 5
$a + $b

The variable $b cannot be retrieved because it has not been set yet.
At line:1 char:7
+ $a + $b <<<<

Jeffrey Snover of MSFT suggested the following (shorter) way of implementing yesterdays script:

[void][Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")

$myTitle = "Important Question"
$myText1 = "Is PowerShell useful to you ?"

$a = [Windows.Forms.MessageBox]::Show($myText1, $myTitle, "YesNoCancel", "Question")
$myText2 = "You answered: $a"
$a = [Windows.Forms.MessageBox]::Show($myText2, $myTitle, "Ok", "Information")

Quick'n'dirty user interface

The example below shows a quick way to use a standard windows messagebox as a user interface, through Windows Forms.

[void][Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")

$myTitle = "Important Question"
$myText1 = "Is PowerShell useful to you ?"

$a = [Windows.Forms.MessageBox]::Show($myText1, $myTitle,`
    [Windows.Forms.MessageBoxButtons]::YesNoCancel, `
    [Windows.Forms.MessageBoxIcon]::Question)
$myText2 = "You answered: $a"
$b = [Windows.Forms.MessageBox]::Show($myText2, $myTitle, `
    [Windows.Forms.MessageBoxButtons]::Ok, `
    [Windows.Forms.MessageBoxIcon]::Information)

PowerShell, SQL & SMO

On november 30th I showed how to access a SQL Server using ADO. Todays script does excatly the same, but uses SMO instead of ADO:

function ShowAllDB_SMO {
    [void][reflection.assembly]::LoadWithPartialName( "Microsoft.SqlServer.ConnectionInfo" );
    [void][reflection.assembly]::LoadWithPartialName( "Microsoft.SqlServer.SmoEnum" );
    [void][reflection.assembly]::LoadWithPartialName( "Microsoft.SqlServer.Smo" );
    $server = new-object( 'Microsoft.SqlServer.Management.Smo.Server' ) $args[0]
    foreach ($database in $server.databases) {
        $temp0 = $database.ID
        $temp1 = $database.Name
        Write-Output "$temp0 ; $temp1"
    }
}

To use the function:

ShowAllDBs_SMO [server or server\instance]

Oneliner

Todays script is a oneliner that sums up the memory consumption of alle running processes (or rather all visible running processes). It also demonstrates the use of ";" as a line separator

$a = get-process; foreach ($i in $a) {$sum = $sum + $i.workingset}; $sum / 1mb