Category: PowerShell

The $Error variable hold a collection of information, and that’s why using $Error[0] can get to your error message objects.  Also the $Error[0] variable will hold the last error message encountered until the PowerShell session ends.

Sample Console session:
Windows PowerShell
Copyright (C) 2009 Microsoft Corporation. All rights reserved.

PS C:\Users\maxt> $error 
PS C:\Users\maxt>
PS C:\Users\maxt> Ip[config
Ip[config : The term ‘Ip[config’ is not recognized as the name of a cmdlet, function, script file, or operable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:10
+ Ip[config <<<<
    + CategoryInfo          : ObjectNotFound: (Ip[config:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

PS C:\Users\maxt>
PS C:\Users\maxt> $error[0]
Ip[config : The term ‘Ip[config’ is not recognized as the name of a cmdlet, function, script file, or operable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.

At line:1 char:10
+ Ip[config <<<<
    + CategoryInfo          : ObjectNotFound: (Ip[config:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

PS C:\Users\maxt>
PS C:\Users\maxt> $Error[0].InvocationInfo.line
Ip[config
PS C:\Users\maxt> 

Starting a new PowerShell session the $Error will be empty.  Type a bad command “Ip[onfig” and the $Error variable will get populated.  Then we use the $Error[0] to display and access the rest of the information it holds.

Don’t forget to use the Get-Member to expose your PS variable objects.

PS C:\Users\maxt> $Error | Get-Member

   TypeName: System.Management.Automation.ErrorRecord

Name                  MemberType     Definition
—-                  ———-     ———-
Equals                Method         bool Equals(System.Object obj)
GetHashCode           Method         int GetHashCode()
GetObjectData         Method         System.Void GetObjectData(System.Runtime.Serialization.Serializatio
GetType               Method         type GetType()
ToString              Method         string ToString()
CategoryInfo          Property       System.Management.Automation.ErrorCategoryInfo CategoryInfo {get;}
ErrorDetails          Property       System.Management.Automation.ErrorDetails ErrorDetails {get;set;}
Exception             Property       System.Exception Exception {get;}
FullyQualifiedErrorId Property       System.String FullyQualifiedErrorId {get;}
InvocationInfo        Property       System.Management.Automation.InvocationInfo InvocationInfo {get;}
PipelineIterationInfo Property       System.Collections.ObjectModel.ReadOnlyCollection`1[[System.Int32,
TargetObject          Property       System.Object TargetObject {get;}
PSMessageDetails      ScriptProperty System.Object PSMessageDetails {get=& { Set-StrictMode -Version 1;

PS C:\Users\maxt> $Error.InvocationInfo
PS C:\Users\maxt> $Error[0].InvocationInfo

MyCommand        :
BoundParameters  : {}
UnboundArguments : {}
ScriptLineNumber : 1
OffsetInLine     : 9
HistoryId        : -1
ScriptName       :
Line             : ip[onfig
PositionMessage  :
                   At line:1 char:9
                   + ip[onfig <<<<
InvocationName   : ip[onfig
PipelineLength   : 0
PipelinePosition : 0
ExpectingInput   : False
CommandOrigin    : Internal

Finally, we can get deeper in the $Error[0] object to extract the line that failed during execution.  If you need to display the failed command line you can use the following line:

$Error[0].InvocationInfo.line

PS C:\Users\maxt> $Error[0].InvocationInfo.line
ip[onfig
PS C:\Users\maxt>

It’s all about understanding your .NET objects.  Hope this help!
🙂

Whaoo! After hours searching the internet for some code that could simply help me automate my Telnet sessions, and not finding a simple solution was frustrating. I had to give up and admit that this one goes to VBScript. YES! I said this one goes to VBScript. But, WAIT A SECOND! PowerShell can provide some leverage when you combine these two scritping technologies. Again, it’s all about integrating technologies to help you be productive and efficient at work.

Let’s cut to the chase and here’s the low down. Many you have been wondering How Can I Automate my Telnet session? Well, VBScript have provided some means to do this for some time. Now, I can use PowerShell to make it more pretty.

Here’s the sample VBScript code use to send commands to a Telnet session: (keep in mind, I’m connecting to Microsoft Telnet in this scenario)

[sourcecode language=”vbscript”]
set oShell = CreateObject("WScript.Shell")
oShell.run("Telnet")
WScript.Sleep 1000
oShell.SendKeys("Open 127.0.0.1 23")
WScript.Sleep 1000
oShell.SendKeys("{Enter}")
WScript.Sleep 1000
oShell.SendKeys("n")
WScript.Sleep 1000
oShell.SendKeys("{Enter}")
WScript.Sleep 1000
oShell.SendKeys"MyName"
WScript.Sleep 1000
oShell.SendKeys("{Enter}")
WScript.Sleep 1000
oShell.SendKeys("MyPassword")
WScript.Sleep 1000
oShell.SendKeys("{Enter}")
WScript.Sleep 1000
oShell.SendKeys("MyCommand")
WScript.Sleep 1000
oShell.SendKeys("{Enter}")
WScript.Sleep 1000
[/sourcecode]

This is, in it basic form,  and with no complexity. Now, using PowerShell we can make it a little more functional by automating the process. I decided to add a text file containing a list of Telnet commands I want to automatically execute during my session. Then, I created a PowerShell function that will build and then execute my auto-generated VBScript.

My command list text file “cmdlist.txt” contains 2 commands for testing purpose and it’s stored in my C:\Temp folder:
Help
Exit

Now, Here’s my “Connect-MyTelnet” function (in its basic form) prototype which put everything together:

[sourcecode language=”powershell”]
function Connect-MyTelnet{
Param(
[string] $IPAddress,
[string] $Port,
[string] $UserName,
[string] $Password,
[string] $cmdlistPath
)
## – Setting default values:
if($port -eq $null){ $Port = "23"; };
if($cmdlistPath -eq $null) { $CmdlistPath = ‘c:\temp\cmdlist.txt’; };

## create vbscript file: MyTelnetSession.vbs
## – For Microsoft Telnet:
$MyVBScript = @"
set oShell = CreateObject("WScript.Shell")`r`n
oShell.run("Telnet")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("Open $IPAddress $Port")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("{Enter}")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("n")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("{Enter}")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("$UserName")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("{Enter}")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("$Password")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("{Enter}")`r`n
WScript.Sleep 1000`r`n
"@;

## – Get file with telnet commands:
[array] $Cmdlist = Get-Content $cmdlistPath;

## loop through and build each telnet command line:
foreach($cmd in $cmdlist)
{
## – Build VBscript lines:
$MyVBScript += ‘oShell.SendKeys("’+$cmd+’")’+"`r`n";
$MyVBScript += "WScript.Sleep 1000`r`n";
$MyVBScript += ‘oShell.SendKeys("{Enter}")’+"`r`n";
$MyVBScript += ‘WScript.Sleep 1000’+"`r`n";
}

## – Close Telnet Session:
$MyVBScript += ‘oShell.SendKeys(" QUIT")’+"`r`n";
$MyVBScript += "WScript.Sleep 1000`r`n";
$MyVBScript += ‘oShell.SendKeys("{Enter}")’+"`r`n";
$MyVBScript += ‘WScript.Sleep 1000’+"`r`n";

## – Save and execute generated VBscript:
$MYVBScript | Out-File -FilePath c:\temp\MyTelnet.vbs -Encoding ASCII;
& c:\temp\MyTelnet.vbs
}; Set-Alias ct Connect-MyTelnet;

[/sourcecode]

Save the above code as a “Connect-MyTelnet.ps1”, then to load in PowerShell use the “. ./Connect-MyTelnet.ps1″ from the folder you saved the file. Finally, to execute run the following one-liner:

[sourcecode language=”powershell”]
Connect-MyTelnet `
-IPAddress ‘127.0.0.1’ `
-Port 23 -UserName Max `
-Password ‘$mypasword1!’ `
-CmdlistPath c:\temp\cmdlist.txt;

[/sourcecode]

This will create/execute the vbscript that will open a Microsoft Telnet session and submit a series of Telnet commands. Now you got something to work and play.

Bonus!!

If you want to use “PuttyTel.exe” just substitute the PowerShell VBscript code to the following:

[sourcecode language=”powershell”]
## – For PuttyTel:
$MyVBScript = @"
set oShell = CreateObject("WScript.Shell")`r`n
oShell.run("c:\temp\PuttyTel")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("$IPAddress")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("{Enter}")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("$UserName")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("{Enter}")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("$Password")`r`n
WScript.Sleep 1000`r`n
oShell.SendKeys("{Enter}")`r`n
WScript.Sleep 1000`r`n
"@;

[/sourcecode]

It’s Friday and I’m following Jeffery Hicks idea to have fun with PowerShell.  Well, here’s the mistery of Redrum solved one more time.  Some time ago, I remember seen some code for reversing a string of characters.  Well, here’s the one-liner I use to solve the puzzle:

[sourcecode language=”powershell”]
$str = "Redrum";
[System.Array]::Reverse(([Array]$RevStr = $str.ToCharArray()));
foreach($chr in $RevStr){ $mistery += $chr }
$mistery;
[/sourcecode]

That’s all for now…. Have fun with PowerShell!

Back in January, I did a quick blog about “Use PowerShell to submit SQLServicePack job to multiple Server“, in that script I have PowerShell to always prompt me for credentials.  But, after a while of typing over and over my password, I found to way to automate my credentials.   Yes!  By automating the credential step, I just could schedule the job, and have time to work with something else.

In this example, I’m passing my credential to the “Start-Transfer” command, so I can do my file download to my destination folder.  Here’s the code snippet to accomplish the automation:

[sourcecode language=”powershell”]
## – Automate to create your credential:
$MyUserName = "Domain\Username";
$MyPassword =  ConvertTo-SecureString ‘MyPwd001!’ -asplaintext -force;
$MyCredentials = new-object `
-typename System.Management.Automation.PSCredential `
-argumentlist $MyUserName,$MyPassword;

## – Import the module and start the download process of one file:
Import-Module BitsTransfer;
Start-BitsTransfer `
-Credential $MyCredentials `
-Source ‘http://YoufilesSite/Files/Demo01.zip’ `
-Destination ‘\\YourServer\NetworkSharedFolder\Demo01.zip’;
[/sourcecode]

Ha!  I know what you’re think!  I’m hardcoding my password in the scripts.  So, our possible options would be: 1) you’re the only one running this script (don’t tell your boss),  2) You trust your Network security (humm!), or 3) find the way to encrypt the script so no one can guess the password.

There are products like SAPIEN’s PrimalScript and PrimalForms, that will let you create an executable out of your script, and then you can deploy it to your server.  But, then again, only you can make that decision.  I’m just showing that’s possible in case you need it.

Have fun with PowerShell!