Power Tips

Creating Large Dummy Files With .NET

ps1 — Thu, 11 Mar 2010 14:00:00 GMT

You can always resort to the underlying .NET framework whenever the functionality you need isn't available through a cmdlet.

The following code is a very fast way to generate really large test files:

$path = "$env:temp\testfile.txt"
$file = [io.file]::Create($path)
$file.SetLength(1gb)
$file.Close()
Get-Item $path

ReTweet this Tip!

Creating Large Dummy Files

ps1 — Wed, 10 Mar 2010 14:00:00 GMT

Sometimes, it is more efficient to use existing console tools rather than PowerShell cmdlets. For example here is a way to create a large file for load tests:

fsutil file createnew $env:temp\dummy.bin (1gb)

However, you should note that fsutil requires admin privileges.

ReTweet this Tip!

Running PowerShell Scripts as Scheduled Task

ps1 — Tue, 09 Mar 2010 14:00:00 GMT

If you have jobs that need to execute regularly, you can manage them with a PowerShell script and make it a scheduled task:

schtasks /CREATE /TN CheckHealthScript /TR "powershell.exe `
-noprofile -executionpolicy Unrestricted `
-file %public%\checkhealth.ps1" /IT /RL HIGHEST /SC DAILY

To remove the scheduled task, specify the name you assigned:

schtasks /DELETE /TN CheckHealthScript

ReTweet this Tip!

Launching a PowerShell Script Externally

ps1 — Mon, 08 Mar 2010 14:00:00 GMT

To launch a PowerShell script outside of the PowerShell console (i.e. as scheduled task or as a link), prepend the script path with this:

Powershell.exe -noprofile -executionpolicy Bypass c:\pathtoscript.ps1

As you can see, in v.2 Microsoft added an -executionPolicy parameter, which allows you to override whatever execution policy is set by default. However, your call cannot override this setting if the execution policy was defined by a group policy.

ReTweet this Tip!

Accessing Profile Scripts

ps1 — Fri, 05 Mar 2010 14:00:00 GMT

Profile scripts are executed automatically when PowerShell starts. The paths to these scripts can be found in $profile:

$profile | gm *Host* | % { $_.Name } | % {
$rv = @{}; $rv.Name = $_
$rv.Path = $profile.$_
$rv.Exists= (Test-Path $profile.$_)
New-Object PSObject -Property $rv
} | Format-Table -AutoSize

Name Path Exists
---- ---- ------
AllUsersAllHosts C:\Windows\...ps1 True
AllUsersCurrentHosts C:\Windows\...ps1 False
CurrentUserAllHosts C:\Users\...ps1 True
CurrentUserCurrentHost C:\Users\...ps1 True

ReTweet this Tip!

Listing Execution Policies

ps1 — Thu, 04 Mar 2010 14:00:00 GMT

In PowerShell v.2, there are multiple execution policies. You should use this to view and check the settings:

Get-ExecutionPolicy -List

ReTweet this Tip!

Closing a Program Gracefully

ps1 — Wed, 03 Mar 2010 14:00:00 GMT

When you use Stop-Process to kill a program, it will stop instantaneously. The user will get no chance to save unsaved documents:

Get-Process Notepad | Stop-Process

Try a more graceful way by using an internal .NET method, which then acts as if someone closed the program window. If the content has not been saved, a dialog opens and asks for a choice:

Get-Process Notepad |
Foreach-Object { $_.CloseMainWindow() | Out-Null }

ReTweet this Tip!

Stopping a Program Whenever You Feel Like It

ps1 — Tue, 02 Mar 2010 14:00:00 GMT

When you launch a program using Start-Process with -passThru, you will get back the process object representing the started program. You can then use this object later to kill the program whenever necessary.

$notepad = Start-Process notepad -passthru
Start-Sleep 2
Stop-Process -inputObject $notepad

ReTweet this Tip!

Use CHOICE to Prompt for Input

ps1 — Mon, 01 Mar 2010 14:00:00 GMT

PowerShell can run native console applications, which can be very helpful. For example, you should take a closer look at CHOICE.EXE, which will prompt you for information:

Choice /N /C:123 /M "Enter a number between 1 and 3!"
"Your choice: $LASTEXITCODE"

This will get you a simple Y/N prompt:

Choice /N /C:YN /M "Do you agree (Y/N)?"
"Your answer: $LASTEXITCODE"

ReTweet this Tip!

Launching Programs Maximized

ps1 — Fri, 26 Feb 2010 14:00:00 GMT

Start-Process has a parameter called -WindowStyle. With it, you can control the window size of the application you launch. You should use this line to launch notepad maximized:

Start-Process notepad -WindowStyle Maximized

Supported arguments are Maximized, Minimized, Normal, and Hidden. Be sure to watch out with Hidden! You should only use it for programs that do not require user interaction.

ReTweet this Tip!

Wait for Programs

ps1 — Thu, 25 Feb 2010 14:00:00 GMT

PowerShell launches Windows applications asynchronously. It only waits for the console application so you should use -wait if you want to launch a Windows application and wait for it until it finishes:

Start-Process notepad -wait

ReTweet this Tip!

Open Current Folder in Your Explorer

ps1 — Wed, 24 Feb 2010 14:00:00 GMT

If you are stuck in the console and would like to move over to the Explorer GUI, the next line opens your current folder in an Explorer window:

explorer .

Of course, this only works when the current folder is set to a folder in your file system.

ReTweet this Tip!

Search for Localized Keywords

ps1 — Tue, 23 Feb 2010 14:00:00 GMT

Finding the appropriate command for a task is important. With a little trick, PowerShell can help you. Have a look:

function ??($keywords) { Get-Help * |
? { $_.description -like "*$keywords*" } |
Select-Object Name, Synopsis }

This function called "??" searches Help content for any keyword you specify. Since Help files are localized, you can happily use keywords in your own language (the language your window uses, to be exact). For example, on German systems, you could search for "Drucker" and get back everything related to "printer":

?? drucker
?? zufall

ReTweet this Tip!

Filter is Faster Than Include

ps1 — Mon, 22 Feb 2010 14:00:00 GMT

A number of cmdlets provide two parameters that seem to work very similar: -filter and -include:

Dir $env:windir -filter *.log
Dir $env:windir -include *.log

If you have a choice, you should always pick -filter. For starters, it is much faster (4x and more) and secondly, -include only works when combined with -recurse. -filter always works.

So why is there -include at all? Because not all providers support -filter. For example, you are limited to -include when you list registry content.

ReTweet this Tip!

Use Online Help

ps1 — Fri, 19 Feb 2010 14:00:00 GMT

"To ship is to choose", so the Help files provided by PowerShell are sometimes outdated. You should use their online versions if you want to get the most accurate and up-to-date information:

Get-Help Get-Process -online

This will open a Web page with the most current version. However, it will only work on U.S. systems because of a documentation bug that you can see on localized versions:

@((get-help get-random).relatedlinks.navigationLink)[0]

As it turns out, Microsoft has added a comment "this may be in English" to the URL, so the URL breaks and you just get a bing search window on these systems.

ReTweet this Tip!