Tips - Appropriate way to have an output.md

Quick Tips about appropriate ways to have an output

Good : Only for on-screen output

Get-Stuff |
    Format-Table Prop1, @{n='CalculatedProp';e={$_.ExtraStuff}}

Bad : Format cmdlet passing down the pipe

Get-Stuff |
    Format-Table Prop1, @{n='CalculatedProp';e={$_.ExtraStuff}} |
    Export-Csv "C:\results.csv"

The Format-Table cmdlet is designed to Out- cmdlets only

Fixed : Selecting when passing down the pipeline

Get-Stuff |
    Select-Object Prop1, @{n='CalculatedProp';e={$_.ExtraStuff}} |
    Export-Csv "C:\results.csv" Appropriate way to have an output

Explanations

Let's take some samples

Get-Service |
    Format-Table Name, @{n='DisplayName';e={$_.DisplayName}} | Get-Member
   TypeName : Microsoft.PowerShell.Commands.Internal.Format.FormatStartData

Name                                    MemberType Definition
----                                    ---------- ----------
Equals                                  Method     bool Equals(System.Object obj)
GetHashCode                             Method     int GetHashCode()
GetType                                 Method     type GetType()
ToString                                Method     string ToString()
autosizeInfo                            Property   Microsoft.PowerShell.Commands.Internal.Format.AutosizeInfo, System.Management.Automation...
ClassId2e4f51ef21dd47e99d3c952918aff9cd Property   string ClassId2e4f51ef21dd47e99d3c952918aff9cd {get;}
groupingEntry                           Property   Microsoft.PowerShell.Commands.Internal.Format.GroupingEntry, System.Management.Automatio...
pageFooterEntry                         Property   Microsoft.PowerShell.Commands.Internal.Format.PageFooterEntry, System.Management.Automat...
pageHeaderEntry                         Property   Microsoft.PowerShell.Commands.Internal.Format.PageHeaderEntry, System.Management.Automat...
shapeInfo                               Property   Microsoft.PowerShell.Commands.Internal.Format.ShapeInfo, System.Management.Automation, V...


   TypeName : Microsoft.PowerShell.Commands.Internal.Format.GroupStartData

Name                                    MemberType Definition
----                                    ---------- ----------
Equals                                  Method     bool Equals(System.Object obj)
GetHashCode                             Method     int GetHashCode()
GetType                                 Method     type GetType()
ToString                                Method     string ToString()
ClassId2e4f51ef21dd47e99d3c952918aff9cd Property   string ClassId2e4f51ef21dd47e99d3c952918aff9cd {get;}
groupingEntry                           Property   Microsoft.PowerShell.Commands.Internal.Format.GroupingEntry, System.Management.Automatio...
shapeInfo                               Property   Microsoft.PowerShell.Commands.Internal.Format.ShapeInfo, System.Management.Automation, V...
# ...

Get-Service |
    Select-Object -Property Name, @{n='DisplayName';e={$_.DisplayName}} | Get-Member
   TypeName : Selected.System.ServiceProcess.ServiceController

Name        MemberType   Definition
----        ----------   ----------
Equals      Method       bool Equals(System.Object obj)
GetHashCode Method       int GetHashCode()
GetType     Method       type GetType()
ToString    Method       string ToString()
DisplayName NoteProperty System.String DisplayName=Agent Activation Runtime_1058c1
Name        NoteProperty string Name=AarSvc_1058c1

What you are seeing is that Format-Table transforms the objects into a stream of formatting directives. These are then consumed by one of the Out- Cmdlets (Out-Host, Out-File, Out-String, Out-Printer).

This is why you can’t pipe format-table to Export-Csv.