Welcome to Day 7 of my “A Month of PowerShell” series. This series will use the series landing page on this blog at http://blog.waynesheffield.com/wayne/a-month-of-powershell/. Please refer to this page to see all of the posts in this series, and to quickly go to them.
Sending messages to the user
PowerShell provides several different cmdlets to allow the PowerShell script to send informational messages to the user. This table shows several of them:
| Write-Debug | Writes a debug message to the console. Uses $DebugPreference variable or -debug parameter |
| Write-Error | Writes an error to the error stream. |
| Write-EventLog | Writes an event to the event log. Requires PowerShell run as administrator |
| Write-Host | Writes output to a host. |
| Write-Output | Sends specified objects to next command in pipeline, or console if last command. |
| Write-Progress | Displays a progress bar – does not display if $ProgressPreference = SilentlyContinue |
| Write-Verbose | Writes text to the verbose message string. Uses $VerbosePreference or -Verbose on any command. |
| Write-Warning | Writes a warning message. |
There are many optional parameters for these, so don’t forget to read the help for the cmdlets. A quick example of several of these:
$DebugPreference = "SilentlyContinue"
Write-Debug "A fantastic, helpful debug message"
Write-Debug "A fantastic, helpful debug message" -Debug
$DebugPreference = "Continue"
Write-Debug "A fantastic, helpful debug message"
$DebugPreference = "SilentlyContinue"
$File = "X:\temp\output.txt"
if (!(Test-Path $File)) {Write-Error "File $File not found!"}
Write-Host "Here's a message for you!"
Write-Warning "Here's a colored message for you!"
Write-Verbose "Searching the Application Event Log" -Verbose
$ProgressPreference
for ($i = 1; $i -le 100; $i++)
{
Write-Progress "Search in Progress" -Status "$i% Complete:" -PercentComplete $i;
}Getting Input from the user
The Read-Host cmdlet allows the script to prompt the user for input, and it waits until text has been entered.
Sending output to other locations
PowerShell provides several cmdlets to pipe output to other locations as well, as the following table shows:
| Out-Null | Deletes output instead of sending it down the pipeline |
| Out-Host | Sends output to the command line |
| Out-File | Sends output to a file |
| Out-Printer | Sends output to a printer |
| Out-String | Sends objects to the host as string. |
| Out-Default | Sends output to the default formatter and to the default output cmdlet. |
| Out-GridView | Sends output to an interactive table in a separate window |
The following script will send all of the processes to the appropriate output:
Get-Process | Out-Null
Get-Process | Out-Host
Get-Process | Out-File $env:TEMP\ProcessList.txt
Get-Process | Out-Printer
Get-Process | Out-String
Get-Process | Out-Default
Get-Process | Out-GridView
