I decided that the logging I was doing in my scripts was not good enough, so I started to learn log4net. Now that posed a problem.

Log4Net is not exactly built for powershell, but it is .Net capable.

The following is my test-log script which requires the .Net 2.0 log4net.dll and log4net.config (XML File) to be in the run directory:
# ==============================================================================================
#
# Microsoft PowerShell Source File -- Created with SAPIEN Technologies PrimalScript 2007
#
# NAME:
#
# AUTHOR: Jason Rydstrand
# DATE  : 2/14/2009
#
# COMMENT: This is a work in progress to show off the ability of log4net in powershell.
#   Currently this requires the log4net.dll and the log4net XML config file to
#   be in the same directory as the script.
#
# ==============================================================================================

 
The following is the contents of my log4net.config file:
<log4net>
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<!-- FileAppender Values -->
<file value="C:\Powershell\testing\" />
<appendToFile value="true" />
<rollingStyle value="Date" />
<staticLogFileName value="false" />
<datePattern value="yyyy\-MM\-dd\-\l\o\g\t\e\s\t\.\l\o\g" />

<!-- Console uses PatternLayout -->
<layout type="log4net.Layout.PatternLayout">
<!-- Print the date in ISO 8601 format -->
<conversionPattern value="%newline%date [%thread] %-5level [%x] - %message%newline" />
</layout>
</appender>
<root>
<level value="INFO" />
<appender-ref ref="RollingLogFileAppender" />
</root>
</log4net>
What this does is setup a RollingLogFileAppender that will roll the log file once a day. The log file will be named year-month-day-logtest.log. As you can see in my scripts, I currently use c:\powershell\testing as my working directory, so you will need to change this to what you use.

My goal at this point is to figure out how to create a date/time log file name that will create a new file on each run with out rolling it on the date. There are many other examples on how to do a Console Log, and I have used them, but was unable to figure out how to convert them into a true log file output.

The following script is fairly well commented. I thank the userserv of #Powershell on Freenode for helping me troubleshoot this, and one user (twometertwo) who wrote the baises of code for this.
# ==============================================================================================
#
# Microsoft PowerShell Source File -- Created with SAPIEN Technologies PrimalScript 2007
#
# NAME: Get-ADUsers
#
# AUTHOR: Jason Rydstrand
# DATE  : 2/6/2009
#
# COMMENT: This script is to Poll AD for a list of all users and their contact information.
#     For more information on Searching AD in Powershell:
#     http://www.microsoft.com/technet/scriptcenter/topics/winpsh/searchad.mspx
#
# ==============================================================================================

This is primarly for Powershell V1 as V2 has a Write-Event or something like that.

I will come back and clean this up at some point along with the other post.
# Variables

$EventLog = New-Object System.Diagnostics.EventLog($EventLogTarget)
$EventLog.MachineName = $EventTarget
$EventLog.Source = $EventSource
$EventLog.WriteEntry($EventText,$ErrorLevel,$EventID)

I will come back and explain this tonight.

For now here is the code block.
foreach ($file in Get-ChildItem -Recurse) { if ($file.Name -match "\[test\]") { Move-Item -literal $file.Name $($file.Name -replace "\[test\]", "") }}

I found this on the Black Mountain blog by sepeck and felt I needed to log it on my own site as a reminder to myself.
# Function to get and calculate drives and free space
# Defaults to localhost if no following name is entered
function Get-DriveSpace([string]$SystemName = "localhost") {
$driveinfo = get-wmiobject win32_logicaldisk -filter "drivetype=3" -computer $SystemName
$driveinfo | select deviceid, `
@{Name="FreeSpace";Expression={($_.freespace/1GB).tostring("0.00")}}, `
@{Name="DriveSize";Expression={($_.size/1GB).tostring("0.00")}}, `
@{Name="Percentfree";Expression={((($_.freespace/1GB)/($_.size/1GB))*100).tostring("0.00")}}
}

An interesting question was posed today on the #powershell channel on Freenode of how to pass exit codes from powershell.

The user was trying to pass them to a command shell, and the %errorlevel% was not being set.

The following is a example of how to do this (saved in file C:\testing.ps1):
$condition = 1

Write-Host "Did not set"
To run the script and have the errorlevel passed to the CMD Console:
C:\>powershell -Command "& { c:\testing.ps1; exit $LASTEXITCODE }"
To check that it set:
C:\>echo %errorlevel%
This one will also work in powershell by just running the script with:
PS C:\>.\testing.ps1
To check that it set:
PS C:\>$LASTEXITCODE
There are other methods of doing this, but those methods will either run the Write-Host every time, or will close the powershell console when ran inside powershell itself.

One thing too add. The code at the top technically is bad form. The proper way to write it would be as follows:
function DoSomething
  {

DoSomething
By writeing it this way, you can call your function that has error code capability and see that it failed on that function, and it will exit before running the next function.

Example:
function DoSomething
  {

Write-Host "`$condition1 and `$condition2 did not meet."
If you change $condition1 to something other then 1, the next function will run and exit out. If you also change $condition2 to something other then 1, both the else statements will run, and the last Write-Host will run.

The Exit code if it runs all the way through will be set to 0. Meaning a good run.