PowerShell text output vs. console output

Question

I'm building a script to monitor my event logs. This command gathers only "Error" and "Warning" messages and places them into the $entries array.

$entries = $log.Entries | ? {$_.TimeWritten -gt ($(Get-Date).AddDays(-2)) -and ` (($_.EntryType -like "Error") -or ` ($_.EntryType -like "Warning"))} | Format-Table -wrap 

If I output $entries in the console, it displays what I want - the log entries - but if I pipe this out to a text file (Add-Content $output $entries) I get the .NET class name only (System.Diagnostics.EventLogEntry). I have also tried foreach ($entry in $entries) with similar results.

What's the basic PowerShell principle I'm missing here?

Answer 1

Basically - the add-content/set-content command just do a ToString() on whatever you pass to it. For many .NET objects, that is just the class name.

If you do:
out-string -inputobject $entries | add-content "yourfile.txt"

That should properly convert to a string and output it to your text file.

Answer 2

Add-content will give you this behavior, if you want the fields rather than the object description then the simplest approach is to just use traditional file redirection e.g.

$entries > $output 

or

$entries >> $output 

if you want to append. This works as I would expect it to for your example code while your example of

Add-Content $output $entries 

Only outputs the object type description (e.g. Microsoft.PowerShell.Commands.Internal.Format.FormatEntryData ) for me.

Answer 3

Piping via: | Add-Content $output

does not appear to work well, when the content being piped contains numerous lines.

For example:

$output = "C:\temp\test.txt" $TimeStamp = Get-Date; "STARTED: " + $TimeStamp | Out-File $output -width 800 Get-ItemProperty -path "HKLM:\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\" | Add-Content $output 

In the above example, the test.txt file gets properly created, including the opening comment. However, the Get-ItemProperty output appears as Chinese characters.