Creating Reports in PowerShell (Part 1 of 3)

One of the most common scripts I see PowerShell newcomers tackle is the "server inventory" script. This will often involve several sections of output, and the scripts often turn out looking something like this:

param (    [string]$computername = $(Read-Host "Enter computer name"))Write-Host "----------- COMPUTER SYSTEM ------------"$cs = Get-WmiObject -Class Win32_ComputerSystem -computername $computername$bios = Get-WmiObject -class Win32_BIOSWrite-Host "Computer: $($cs.Name)"Write-Host "Manufacturer: $($cs.Manufacturer)"Write-Host "Model: $($cs.Model)"Write-Host "BIOS Serial: $($bios.SerialNumber)"Write-Host ""Write-Host "----------- OPERATING SYSTEM -------------"Get-WmiObject -Class Win32_OperatingSystem -computername $computername | Select-Object -Property Version,BuildNumber,ServicePackMajorVersion,OSArchitecture |Format-ListWrite-Host ""Write-Host "----------- PROCESSORS -------------"Get-WmiObject -class Win32_Processor  -computername $computername |Select-Object -Property AddressWidth,MaxClockSpeed -First 1 |Format-ListWrite-Host ""Write-Host "----------- DISKS -------------"Get-WmiObject -class Win32_LogicalDisk -filter "drivetype=3" -computername $computername |Select-Object -Property DeviceID,Size,FreeSpace |Format-List

This just makes me die a little inside, unfortunately. The first clue that something's wrong is the profligate use of Write-Host. I know what folks are trying to accomplish, but they're just going about it the wrong way. 

Specific problems:

To really see what's wrong with this approach, try copying it and pasting it into the PowerShell ISE on your computer. Save it as c:test.ps1 or something. Then run it like this:

./test | Out-File results.txt

The text file will be awful, and not look at all like what was on the screen. A seemingly-easy fix would be to replace all the Write-Host calls with Write-Output instead. That'll get a more consistent-looking file. Sort of. But it'll still be awful.

I'm going to present two fixes for this situation, and present them in a way that you can use as a template to build on, if you want to.