What To Do / Not to Do in PowerShell: Part 3

Take a look at the left-hand side of your keyboard. Odds are, you'll find a key labeled "Tab," or perhaps a key with a "->" symbol on it. Also notice a key labeled "Enter" or "Return," and that big, blank key at the ver bottom.

Please make these keys your friend.

Why? Take a look at this code:
 

function Get-Info {[CmdletBinding()]param([Parameter(Mandatory=$True,ValueFromPipeline=$True,ValueFromPipelineByPropertyName=$True)][Alias('host')][string[]]$computername,[string]$logfile='c:failed.txt')BEGIN {Del $logfile -ErrorAction 'SilentlyContinue'}PROCESS {foreach ($computer in $computername) {try {           $continue=$true      write-verbose "Attempting connection to $computer"    $os = Get-WmiObject -class Win32_OperatingSystem -ComputerName $computer -ErrorAction 'Stop'} catch {  $computer | Out-File $logfile -append                         $continue = $False            }if ($continue) {    $bios = Get-WmiObject -class Win32_BIOS -ComputerName $computer $obj = New-Object -TypeName PSObject $obj | Add-Member -MemberType NoteProperty -Name ComputerName -value ($computer) -passthru |Add-Member -MemberType NoteProperty -Name OSVersion -value ($os.caption) -passthru |Add-Member -MemberType NoteProperty -Name OSBuild -value ($os.buildnumber) -passthru |Add-Member -MemberType NoteProperty -Name SPVersion -value ($os.servicepackmajorversion) -passthru |Add-Member -MemberType NoteProperty -Name BIOSSerial -value ($bios.serialnumber)  write-output $obj  } } }}

Pretty awful, isn't it? It's hard to read. It's even harder to debug, because it's so poorly-formatted. Whenever I'm teaching class, I tell my students: "If you need help, just ask. But, if your code looks anything like this," and I show them the example above, "don't bother!" I just can't read it.

Now, isn't this version much easier to read and interpret?
 

function Get-Info {    [CmdletBinding()]    param(        [Parameter(Mandatory=$True,ValueFromPipeline=$True,ValueFromPipelineByPropertyName=$True)]        [Alias('host')]        [string[]]$computername,        [string]$logfile = 'c:failed.txt'    )    BEGIN {        Del $logfile -ErrorAction 'SilentlyContinue'    }    PROCESS {        foreach ($computer in $computername) {            try {                $continue = $true                write-verbose "Attempting connection to $computer"                $os = Get-WmiObject -class Win32_OperatingSystem -ComputerName $computer -ErrorAction 'Stop'            } catch {                $computer | Out-File $logfile -append                $continue = $False            }            if ($continue) {                $bios = Get-WmiObject -class Win32_BIOS -ComputerName $computer                $obj = New-Object -TypeName PSObject                $obj | Add-Member -MemberType NoteProperty -Name ComputerName -value ($computer) -passthru |                       Add-Member -MemberType NoteProperty -Name OSVersion -value ($os.caption) -passthru |                       Add-Member -MemberType NoteProperty -Name OSBuild -value ($os.buildnumber) -passthru |                       Add-Member -MemberType NoteProperty -Name SPVersion -value ($os.servicepackmajorversion) -passthru |                       Add-Member -MemberType NoteProperty -Name BIOSSerial -value ($bios.serialnumber)                write-output $obj            }        }    }}

The difference? Tabs. Spaces. Carriage returns. Code within a { construct } of some kind is indented exactly four characters (one tab). That series of Add-Member statements are formatted to line up, visually reminding me that they're all part of the same logical command - see the pipe character at the end of each? PowerShell will recognize that the command continues on the next line when a line ends in a pipe. 

It's just a bit of whitespace, but it makes all the difference in the world. So please, format your code!