Archive for April, 2012
PowerShell news April 2012
As April comes to close so does the extension for grading scripts in the recent games. I’ve been so busy grading haven’t had time to blog about the games. I’ll start to catch up on the backlog over the next few weeks. This years games have been huge with more than 150% growth in the number of scripts submitted. That is a lot of PowerShell.
The Deep Dive starts tonight – with keynotes tomorrow. This is shaping up to be the PowerShell event of the year.
Powershell and WMI will be available very soon.
Advanced Powershell – http://www.manning.com/jones2/ is well on the way and still on target for a release soon after Windows 8 and Powershell v3
Windows 8/windows 2012 release candidate will be with us in early June. Already had one user group session on the topic and there will be another one in May
UK PowerShell Group–April 2012 slides and recording
The slides, demo script and recording are available from
https://skydrive.live.com/?cid=43cfa46a74cf3e96#cid=43CFA46A74CF3E96&id=43CFA46A74CF3E96%212957
Thank you again to everyone who attended the Live Meeting this evening
Reminder–UK User group 24 April
Quick reminder that 24 April sees the first of 2 sessions on new PowerShell functionality in Windows 2012 – Windows Server 8
Details from
http://msmvps.com/blogs/richardsiddaway/archive/2012/04/13/uk-powershell-group-24-april-2012.aspx
Scripting Games 2012 comments: #10 Advanced event 5
This is the one I was asked to supply a commentary for
This one has raised an interesting interpretation issues. The last design point asks:
- Your output should be organized such that the largest source of errors appears at the top of the output.
The figure shows the data sorted by Event source
I read the design point as log with the largest number of errors comes first. The script I produced for the commentary doesn’t meet that last design point so I’ve revised it
#Requires -Version 2 function Get-EventEntryCount{ [CmdletBinding()] param ( [parameter(Position=0, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true)] [Alias("CN", "Computer")] [string[]]$computername="$env:COMPUTERNAME", [parameter(Position=1)] [ValidateSet("Error", "Information", "FailureAudit", "SuccessAudit", "Warning", "All", "*")] [string]$eventtype="Error" ) BEGIN{ $currentUser = [Security.Principal.WindowsIdentity]::GetCurrent() $testadmin = ` (New-Object Security.Principal.WindowsPrincipal $currentUser).IsInRole(` [Security.Principal.WindowsBuiltinRole]::Administrator) if (!$testadmin){ Throw "Must be run with elevated privileges" } }#begin PROCESS{ foreach ($computer in $computername ){ switch ($computer) { "." {$computer="$env:COMPUTERNAME"} "localhost" {$computer="$env:COMPUTERNAME"} } Write-Verbose "Processing computer: $computer" $data = @() if (Test-Connection -ComputerName $computer -Count 1 -Quiet){ Write-Verbose "Starting Remote Registry service on $computer" $origrrsrv = Get-WmiObject -Class Win32_Service -Filter "Name='RemoteRegistry'" ` -ComputerName $computer if ($origrrsrv.StartMode -eq "Disabled") { Set-Service -Name RemoteRegistry -ComputerName $computer -StartupType "Manual" } if ($origrrsrv.State -ne "Running") { $origrrsrv.StartService() | Out-Null } Write-Verbose "Retrieving logs for $computer" Get-EventLog -List -ComputerName $computer | foreach { $log = $_.Log Write-Verbose "Processing log: $log" if ($_.Entries.Count -gt 0) { Write-Debug "Processing event type $eventtype" $n = Get-EventLog -LogName $($_.Log) -EntryType $eventtype -ComputerName $computer ` -ErrorAction SilentlyContinue if ($n -ne $null){ Write-Debug "Entries found" $n | group Source -NoElement | foreach{ $data += New-Object -TypeName PSObject -Property @{ ComputerName = $computer LogName = $log EntryType = $eventtype EntrySource = $($_.Name) EntryCount = $($_.Count) } } } } # end if entries else { Write-Verbose "$($computer): $log is empty" } if ($origrrsrv.State -eq "Stopped") { $origrrsrv.StopService() | Out-Null } if ($origrrsrv.StartMode -eq "Disabled") { Set-Service -Name RemoteRegistry -ComputerName $computer -StartupType "Disabled" } } # end of log processing foreach } else { Write-Warning "Cannot contact $computer" } # end if ping Write-Output $data } ## end computer foreach }#process END{}#end <# .SYNOPSIS Counts the number of entries of a given type in the event logs of a system .DESCRIPTION One or more computers - from pipeline or parameter - are accessed to read the envent logs and count the entries of a given type. Empty logs are tested and the count is set to zero .PARAMETER computername Name of computer for which log information is to be retrieved .PARAMETER eventtype Log entry type to count. Accepted values are - "Error", "Information", "FailureAudit", "SuccessAudit", "Warning", "All", "*" .EXAMPLE Get-EventEntryCount Accesses logs on local machine. Peforms default display .EXAMPLE Get-EventEntryCount -computername "." | sort LogName, EntryCount -Descending | Format-Table EntrySource, EntryCount -GroupBy LogName Accesses logs on local machine. Format display and group by logname .EXAMPLE "dc02", "webr201", "server02" | Get-EventEntryCount | sort Computer, LogName, EntryCount -Descending | Format-Table Logname, EntrySource, EntryCount -GroupBy Computer Accesses logs on remote machines. Computer names accepted from pipeline. Format display and group by computer .EXAMPLE Get-EventEntryCount -computername "dc02", "webr201", "server02" | sort Computer, LogName, EntryCount -Descending | Format-Table Logname, EntrySource, EntryCount -GroupBy Computer Accesses logs on remote machines. Computer names accepted as array. Format display and group by computer .INPUTS Computer name - string or string array Envent type - string. Must be member of set .OUTPUTS Returns a custom object with properties: ComputerName - name of computer LogName - name of log EntryType - Type of log entry EntryCount - count of entries EntrySource - event source .NOTES .LINK #> }
Scripting Games 2012 comments: #9 Beginners event 5
Beginners event 5
Looking for problem applications. Need report from each server form application log listing source and number of errors.
Requirements:
- should be capable of running against remote machine
- doesn’t need to run remotely for this scenario
- don’t need to check for admin rights
- assume have permissions to query application log
- use standard PowerShell cmdlets
- solution should be simple and straightforward
- don’t need to write to text file BUT should should be easily redirectable when needed
- don’t need comment based help
- extra points for sorting so source with greatest number of errors at top of list
Reading the event log using standard PowerShell cmdlets - what do we have available?
Get-Command *event* -CommandType cmdlet
shows a bunch of cmdlets. Lets narrow it down
Get-Command *eventlog* -CommandType cmdlet
shows that Get-EventLog is a good choice.
NOTE: Get-WinEvent is also available but the syntax can be more convoluted. As we are reading a classic event log Get-Eventlog is the simplest solution.
What parameters do we have available?
PS> Get-Help Get-EventLog
NAME
Get-EventLog
SYNOPSIS
Gets the events in an event log, or a list of the event logs, on the local or remote computers.
SYNTAX
Get-EventLog [-AsString] [-ComputerName <string[]>] [-List] [<CommonParameters>]
Get-EventLog [-LogName] <string> [[-InstanceId] <Int64[]>] [-After <DateTime>] [-AsBaseObject]
[-Before <DateTime>] [-ComputerName <string[]>] [-EntryType <string[]>] [-Index <Int32[]>]
[-Message <string>] [-Newest <int>] [-Source<string[]>] [-UserName <string[]>] [<CommonParameters>]
Look at the synopsis – local or remote computers. Computername for local/remote machines. EntryType gives the type of entry. Thats about it.
PS> Get-Help Get-EventLog -Parameter EntryType
-EntryType <string[]>
Gets only events with the specified entry type. Valid values are Error, Information, FailureAudit, SuccessAudit, and Warning. The default is all events.
Required? false
Position? named
Default value All events
Accept pipeline input? false
Accept wildcard characters? false
What does an entry look like?
PS> Get-EventLog -LogName Application | select -f 1 | Format-List
Index : 83084
EntryType : Information
InstanceId : 1073872902
Message : BBSvc has stopped.
Category : (0)
CategoryNumber : 0
ReplacementStrings : {BBSvc}
Source : BBSvc
TimeGenerated : 17/04/2012 18:00:17
TimeWritten : 17/04/2012 18:00:17
UserName :
We have an entry type so we can select on that and we have a source. How can we can the total number of entries per source?
PS> Get-EventLog -LogName Application -EntryType Error | group Source
Count Name Group
—– —- —–
166 SideBySide {System.Diagnostics.EventLogEntry, System.Di
27 Application Error {System.Diagnostics.EventLogEntry, System.Di
1 System Restore {System.Diagnostics.EventLogEntry}
2 Microsoft-Windows-Rest… {System.Diagnostics.EventLogEntry, System.Di
3 VSS {System.Diagnostics.EventLogEntry, System.Di
20 Application Hang {System.Diagnostics.EventLogEntry, System.Di
1 MsiInstaller {System.Diagnostics.EventLogEntry}
All we need is the Count and the name so we can use the –NoElement parameter
PS> Get-EventLog -LogName Application -EntryType Error | group Source -NoElement
Count Name
—– —-
166 SideBySide
27 Application Error
1 System Restore
2 Microsoft-Windows-Rest…
3 VSS
20 Application Hang
1 MsiInstaller
But we want them in descending order – actually requirements state largest number of errors at the top of the list which we already have but we will show willing and actually sort the list 
PS> Get-EventLog -LogName Application -EntryType Error |
group Source -NoElement | sort Count -Descending
Count Name
—– —-
166 SideBySide
27 Application Error
20 Application Hang
3 VSS
2 Microsoft-Windows-Rest…
1 MsiInstaller
1 System Restore
If you want to see the whole name
PS> Get-EventLog -LogName Application -EntryType Error | group Source -NoElement |
sort Count -Descending | Format-table Count, Name -AutoSize
Count Name
—– —-
166 SideBySide
27 Application Error
20 Application Hang
3 VSS
2 Microsoft-Windows-RestartManager
1 MsiInstaller
1 System Restore
We haven’t shown how to access a remote machine
PS> Get-EventLog -LogName Application -EntryType Error -Computername $env:COMPUTERNAME |
group Source -NoElement | sort Count -Descending | Format-table Count, Name –AutoSize
saving to a file:
PS> Get-EventLog -LogName Application -EntryType Error -Computername $env:COMPUTERNAME |
group Source -NoElement | sort Count -Descending | Format-table Count, Name -AutoSize |
Out-File beg5.txt
is legitimate and gives you exactly what you see on screen – though object police will scream at you for using format-table so if you want to conform try
PS> Get-EventLog -LogName Application -EntryType Error -Computername $env:COMPUTERNAME |
group Source -NoElement | sort Count -Descending | Out-File beg5.txt
but long source names may be truncated
if you really want to demonstrate you know what you are doing
PS> Get-EventLog -LogName Application -EntryType Error -Computername $env:COMPUTERNAME |
group Source -NoElement | sort Count -Descending | Tee-Object -FilePath beg5.txt
tee-object writes to a file and passes along pipeline to finally display
don’t use Add-Content or Set-Content as as all you will get is a set of lines like this
Microsoft.PowerShell.Commands.GroupInfoNoElement
These cmdlets don’t resolve the objects to the data
The Get-WinEvent syntax would be
Get-WinEvent -ComputerName $env:COMPUTERNAME -FilterHashtable @{‘LogName’=’Application’; ‘Level’=2}
which to my mind isn’t as simple as Get-EventLog.
And finally if you just can’t live without aliases – get-eventlog doesn’t have one.
PowerShell and WMI
My latest book – PowerShell and WMI – has gone to the printers. Expect it soon at a book shop near you.
www.manning.com/powershellandwmi
for more details
Manning PowerShell book offer
Manning are offering 50% off PowerShell in Practice using code dotd0415cc in the promotional code box at www.manning.com
The same code gets you 50% off PowerShell and WMI AND Advanced PowerShell
This is FOR TODAY ONLY
Scripting Games 2012 comments: #8 Beginners Event 4
Makes sure you run the script provided with the event to get the right folders. The script randomly removes 1 file from each folder – sneaky.
After last nights head scratching this one is much simpler. It’s solvable with one line of PowerShell.
For this one we have a data folder and a back up folder we need to compare.
Requirements:
- Content of backup folder is same as data folder
- Only compare file names
- Show files in one folder that don’t exist in other
- Return file information objects as result of comparison
- Don’t need complicated script
- Unnecessary complexity costs points
- Extra points for native PowerShell cmdlets and code simplicity
We need to deal with file names – so that implies Get-ChildItem. We can see the contents of the files:
Get-ChildItem -Path c:\1
Get-ChildItem -Path c:\2
Do we have anything to do a compare?
Get-Command *compare*
shows we have compare-object.
If you haven’t seen this before – read the help.
In fact as a general rule read the help for all cmdlets before using in the games just to make sure you understand them and you’ve picked up on all the extras that might help you.
PS> get-help Compare-Object
SYNOPSIS
Compares two sets of objects.
SYNTAX
Compare-Object [-ReferenceObject] <PSObject[]> [-DifferenceObject] <PSObject[]>
[-CaseSensitive] [-Culture <string> ] [-ExcludeDifferent] [-IncludeEqual] [-PassThru]
[-Property <Object[]>] [-SyncWindow <int>] [<CommonParameters>]
DESCRIPTION
The Compare-Object cmdlet compares two sets of objects. One set of objects is the Reference set,
and the other set is the Difference set.
The result of the comparison indicates whether a property value appeared only in the object from
the Reference set (indicated by the <= symbol), only in the object from the Difference set
(indicated by the => symbol) or, if the IncludeEqual parameter is specified, in both objects
(indicated by the == symbol).
This means we need to treat the folder contents as objects. PowerShell has a very clever trick we can use here. We put the
Get-ChildItem -Path c:\1
Get-ChildItem -Path c:\2
in parentheses which tells PowerShell to treat them as objects and we can use these directly as input to compare-object.
PS> Compare-Object -ReferenceObject (Get-ChildItem -Path c:\1) -DifferenceObject (Get-ChildItem -Path c:\2)
InputObject SideIndicator
———– ————-
13.txt =>
10.txt <=
That should make sense now you can see what I mean. The alternative would be to do this
PS> $list1 = Get-ChildItem -Path c:\1
PS> $list2 = Get-ChildItem -Path c:\2
PS> Compare-Object -ReferenceObject $list1 -DifferenceObject $list2
InputObject SideIndicator
———– ————-
13.txt =>
10.txt <=
which involves more typing and depending on how you define complexity is more complex.
We can do the compare but we need to restrict the comparison to file names – so we need the –Property parameter. This is why you need to read the help file.
Compare-Object -ReferenceObject (Get-ChildItem -Path c:\1) -DifferenceObject (Get-ChildItem -Path c:\2) -Property Name
This still produces the output above and we were told to output file objects. Once more into the help file and we find –Passthru which “Passes the objects that differed to the pipeline. By default, this cmdlet does not generate any output.”
PS> Compare-Object -ReferenceObject (Get-ChildItem -Path c:\1) -DifferenceObject (Get-ChildItem -Path c:\2) -Property Name -PassThru
Directory: C:\2
Mode LastWriteTime Length Name
—- ————- —— —-
-a— 14/04/2012 15:54 0 13.txt
Directory: C:\1
Mode LastWriteTime Length Name
—- ————- —— —-
-a— 14/04/2012 15:54 0 10.txt
That solves the problem and is as simple as it gets. Oh you want aliases as well.
compare -R (ls c:\1) -Di (ls c:\2) -Pr Name –Pa
And that is why I don’t like aliases because it is no where near as obvious what I am doing.
Scripting Games 2012 comments: #7 update on beginners event 3
It was bugging me that I couldn’t get try-catch work on the folder where I didn’t have permissions. Finally thought of the reason – set the ErrorAction to Ignore. Heres the revised script
[CmdletBinding()] param ( [string]$path = "C:\2012sg\event3", [string]$file = "Process3.txt" ) Write-Verbose "Test path is valid" if (-not (Test-Path -Path $path -IsValid)){ Throw "Invalid path $path" } if (-not (Test-Path -Path $path)){ Write-Verbose "Create Folder" try { $rt = New-Item -Path $path -ItemType Directory -ErrorAction Ignore } catch { $path = (Join-Path -Path $env:HOMEDRIVE -ChildPath $env:HOMEPATH) + (Split-Path -Path $path -NoQualifier) Write-Debug $path New-Item -Path $path -ItemType Directory | Out-Null } } Write-Verbose "Write Process data" Get-Process | Format-Table Name, Id -a | Out-File -FilePath (Join-Path -Path $path -ChildPath $file) <# .SYNOPSIS Creates a folder to hold a file containing process data .DESCRIPTION A folder - by default "C:\2012sg\event3" - is created and a file called "Process3.txt" by default is created holding process data. The process name and id is used to fill the file. Any existing file is over written If the folder can't be created in the root of C: it is created in $env:HOMEDRIVE\$env:HOMEPATH i.e. the users home drive .PARAMETER path Path of the folder we want to create Default is "C:\2012sg\event3" .PARAMETER file File name of file to hold process data Default is "Process3.txt" .EXAMPLE .\beg3.ps1 Runs script with default values .EXAMPLE .\beg3.ps1 -path "c:\testbeg3\event3" -file "testP3.txt" Runs script with values for path and file supplied .EXAMPLE .\beg3.ps1 -Verbose Runs script with verbose output #>
Scripting games 2012 comments: #6 Beginners event 3
Onto event 3 http://blogs.technet.com/b/heyscriptingguy/archive/2012/04/04/2012-scripting-games-beginner-event-3-create-a-file-in-a-folder.aspx where we have to create a file in a folder. Simple – well yes but not with the twists the Scripting Guy throws at you.
The requirements:
- save file in c:\2012sg\event3
- file contains process name and id running on local machine
- file must be called Process3.txt
- if folder doesn’t exist must create it
- if don’t have permissions to root of c: create it somewhere where you do have permissions
- script should not generate errors that are ignored
- script doesn’t need command line parameters but get extra points for including them
- if include command line parameters should include comment based help and sample of using script
Lets start with the file contents. We can find the process information like this
Get-Process
Use a select to restrict the data to the two properties we want
Get-Process | select Name, Id
That looks ugly so lets bring the two columns together so that it’s easier on the eye.
Get-Process | Format-Table Name, Id -a
The PowerShell object police will be screaming at this point because I’m not outputting objects BUT the data is going to end up in a file so it doesn’t matter.
Now we need to get the data into the file
PS> Get-Process | Format-Table Name, Id -a | Out-File -FilePath Process3.txt
PS> Get-Content Process3.txt
Name Id
—- —
armsvc 1764
BingApp 3216
BingBar 3764
bingsurrogate 2692
etc
Even kept the case on the file name!
So we can create a file with the data we need. What about the folder?
It has to be a specific path and if the path doesn’t exist we have to create it. Need to test for existence and create folder if it doesn’t exist.
The trick here is to test for the whole folder path. Ignore the file we are going to create that anywhere. Don’t test for each element in the path – if c:\2012sg\event3 exists then c:\2012 MUST exist. We don’t care about the file because it will be over written if it exists.
There are a number of cmdlets in PowerShell for working with paths
PS> Get-Command *path
CommandType Name
———– —-
Cmdlet Convert-Path
Cmdlet Join-Path
Cmdlet Resolve-Path
Cmdlet Split-Path
Cmdlet Test-Path
We want test-path. If the path DOESN’T exist we need to create it. To get the neatest code we test on the negative of its existence and create the folder
$path = "C:\2012sg\event3"
if (-not (Test-Path -Path $path)){
New-Item -Path "C:\2012sg\event3" -ItemType Directory
}
Test-Path -Path $path
This will return True when we test the second time. The folder information is written to screen
Directory: C:\2012sg
Mode LastWriteTime Length Name
—- ————- —— —-
d—- 13/04/2012 19:47 event3
We can suppress this by adding Out-Null onto the New-Item line
New-Item -Path "C:\2012sg\event3" -ItemType Directory | Out-Null
At this time we have the basis of our entry
if (Test-Path -Path C:\2012sg){ Remove-Item -Path "C:\2012sg" -Recurse -Force } $path = "C:\2012sg\event3" $file = "Process3.txt" if (-not (Test-Path -Path $path)){ New-Item -Path "C:\2012sg\event3" -ItemType Directory | Out-Null } Get-Process | Format-Table Name, Id -a | Out-File -FilePath (Join-Path -Path $path -ChildPath $file)
The first test-path deletes the folder AND contents if it exists. This is useful when testing to ensure you always end up testing the script properly but don’t forget to remove it at some stage so you can test that the script works if the folder exists!
I used Join-Path to create the full path to the file – could have done “$path\$file” or even worse $path + “\” + $file
That has dealt with the first four objectives. Now what if we don’t have permissions to the root of C:
I’m not messing with the permissions on my C: drive but I’ve created a test folder and denied the permissions to create folders and files – typical permissions
This is what happens
PS> New-Item -Path c:\testperm -Name Myfolder -ItemType Directory
New-Item : Access to the path ‘Myfolder’ is denied.
At line:1 char:9
+ New-Item <<<< -Path c:\testperm -Name Myfolder -ItemType Directory
+ CategoryInfo : PermissionDenied: (C:\testperm\Myfolder:String) [New-Item], UnauthorizedAccessException
+ FullyQualifiedErrorId : CreateDirectoryUnauthorizedAccessError,Microsoft.PowerShell.Commands.NewItemCommand
Now we could use Get-Acl to test permissions
PS> Get-Acl -Path c:\testperm | select -ExpandProperty Access |
Format-Table IdentityReference, FileSystemRights, AccessControlType -AutoSize
IdentityReference FileSystemRights AccessControlType
—————– —————- —————–
BUILTIN\Administrators CreateFiles, AppendData Deny
BUILTIN\Administrators FullControl Allow
BUILTIN\Administrators 268435456 Allow
NT AUTHORITY\SYSTEM FullControl Allow
NT AUTHORITY\SYSTEM 268435456 Allow
BUILTIN\Users ReadAndExecute, Synchronize Allow
NT AUTHORITY\Authenticated Users Modify, Synchronize Allow
NT AUTHORITY\Authenticated Users -536805376 Allow
But in reality we don’t know what permissions have been set so potentially we would have to test a lot of permissions. Not easy to get right and we don’t want to generate errors that are ignored.
We also need somewhere to put the file if we can’t get to C:\
You might think that this would work
path = "C:\Testperm\2012sg\event3"
$file = "Process3.txt"
if (-not (Test-Path -Path $path)){
try {
New-Item -Path $path -ItemType Directory |
Out-Null
}
catch {
write-host "oops"
}
}
Get-Process |
Format-Table Name, Id -a |
Out-File -FilePath (Join-Path -Path $path -ChildPath $file)
But it doesn’t because the error message thrown by New-Item isn’t a .NET exception. Its a message to say that the task hasn’t completed
Lets try this
$path = "C:\Testperm\2012sg\event3"
if (-not (Test-Path -Path $path)){
$rt = New-Item -Path $path -ItemType Directory
}
$rt
$path = "C:\2012sg\event3"
if (-not (Test-Path -Path $path)){
$rt = New-Item -Path $path -ItemType Directory
}
$rt
Which captures the two return messages
New-Item : Access to the path ‘event3’ is denied.
At line:4 char:18
+ $rt = New-Item <<<< -Path $path -ItemType Directory
+ CategoryInfo : PermissionDenied: (C:\Testperm\2012sg\event3:String) [New-Item], UnauthorizedAccessException
+ FullyQualifiedErrorId : CreateDirectoryUnauthorizedAccessError,Microsoft.PowerShell.Commands.NewItemCommand
Directory: C:\2012sg
Mode LastWriteTime Length Name
—- ————- —— —-
d—- 13/04/2012 20:29 event3
Working with either of these isn’t going to be easy BUT if the directory doesn’t create we get a error which we can access through the $error automatic variable
$path = "C:\2012sg\event3" $file = "Process3.txt" if (-not (Test-Path -Path $path)){ $rt = New-Item -Path $path -ItemType Directory -ErrorAction SilentlyContinue if (Select-String -InputObject $error[0] -Pattern "event3" -SimpleMatch){ $path = (Join-Path -Path $env:HOMEDRIVE -ChildPath $env:HOMEPATH) + (Split-Path -Path $path -NoQualifier) New-Item -Path $path -ItemType Directory | Out-Null } } Get-Process | Format-Table Name, Id -a | Out-File -FilePath (Join-Path -Path $path -ChildPath $file)
Set the folder creation to silently continue and test the last error message for part of the folder path – if its there something has gone wrong so we swing to creating the folder where we will have permissions – our home drive. A bit of manipulation with the path cmdlets and we have a new path where we can create the folder
get-process can then be used as before
That takes care of the folder creation if no permissions and the error messages being unhandled
At the moment the paths are hard coded but if we want to change then using command line parameters is the best bet. Keep the current as defaults.
param ( [string]$path = "C:\2012sg\event3", [string]$file = "Process3.txt" ) if (-not (Test-Path -Path $path -IsValid)){ Throw "Invalid path $path" } if (-not (Test-Path -Path $path)){ $rt = New-Item -Path $path -ItemType Directory -ErrorAction SilentlyContinue if (Select-String -InputObject $error[0] -Pattern "event3" -SimpleMatch){ $path = (Join-Path -Path $env:HOMEDRIVE -ChildPath $env:HOMEPATH) + (Split-Path -Path $path -NoQualifier) New-Item -Path $path -ItemType Directory | Out-Null } } Get-Process | Format-Table Name, Id -a | Out-File -FilePath (Join-Path -Path $path -ChildPath $file)
We can use it like this to use the defaults
.\beg3.ps1
or like this to put the file somewhere else
.\beg3.ps1 -path "c:\testbeg3\event3" -file "testP3.txt"
Lets add some comments – don’t use # – use write-debug and write-verbose
[CmdletBinding()] param ( [string]$path = "C:\2012sg\event3", [string]$file = "Process3.txt" ) Write-Verbose "Test path is valid" if (-not (Test-Path -Path $path -IsValid)){ Throw "Invalid path $path" } if (-not (Test-Path -Path $path)){ Write-Verbose "Create Folder" $rt = New-Item -Path $path -ItemType Directory -ErrorAction SilentlyContinue if (Select-String -InputObject $error[0] -Pattern "event3" -SimpleMatch){ $path = (Join-Path -Path $env:HOMEDRIVE -ChildPath $env:HOMEPATH) + (Split-Path -Path $path -NoQualifier) Write-Debug $path New-Item -Path $path -ItemType Directory | Out-Null } } Write-Verbose "Write Process data" Get-Process | Format-Table Name, Id -a | Out-File -FilePath (Join-Path -Path $path -ChildPath $file)
Which means we can do this – all for adding [CmdletBinding()] to the top of the script
PS> .\beg3.ps1 -Verbose
VERBOSE: Test path is valid
VERBOSE: Write Process data
last job is add the help
[CmdletBinding()] param ( [string]$path = "C:\2012sg\event3", [string]$file = "Process3.txt" ) Write-Verbose "Test path is valid" if (-not (Test-Path -Path $path -IsValid)){ Throw "Invalid path $path" } if (-not (Test-Path -Path $path)){ Write-Verbose "Create Folder" $rt = New-Item -Path $path -ItemType Directory -ErrorAction SilentlyContinue if (Select-String -InputObject $error[0] -Pattern "event3" -SimpleMatch){ $path = (Join-Path -Path $env:HOMEDRIVE -ChildPath $env:HOMEPATH) + (Split-Path -Path $path -NoQualifier) Write-Debug $path New-Item -Path $path -ItemType Directory | Out-Null } } Write-Verbose "Write Process data" Get-Process | Format-Table Name, Id -a | Out-File -FilePath (Join-Path -Path $path -ChildPath $file) <# .SYNOPSIS Creates a folder to hold a file containing process data .DESCRIPTION A folder - by default "C:\2012sg\event3" - is created and a file called "Process3.txt" by default is created holding process data. The process name and id is used to fill the file. Any existing file is over written If the folder can't be created in the root of C: it is created in $env:HOMEDRIVE\$env:HOMEPATH i.e. the users home drive .PARAMETER path Path of the folder we want to create Default is "C:\2012sg\event3" .PARAMETER file File name of file to hold process data Default is "Process3.txt" .EXAMPLE .\beg3.ps1 Runs script with default values .EXAMPLE .\beg3.ps1 -path "c:\testbeg3\event3" -file "testP3.txt" Runs script with values for path and file supplied .EXAMPLE .\beg3.ps1 -Verbose Runs script with verbose output #>
I always add help at the end. check about_comment_based help for further details