Scripting as a Second Language

Admin
Scripting as a Second Language
Rob Dunn
October 20th, 2011

…seen a VBScript (or other) before and have used
one in your network
…downloaded one from the Spiceworks Script
Center
…dabbled in VBScripting but don’t know where to
go next
…wanted to get a little more from your current
scripting skills

Assumptions

• Anatomy of a VBScript (5 major elements)
• Error Handling
• Copying, Reading from, Writing to a file
• Reading command-line results
• Getting WMI and Active Directory Information
• Building a GUI for your scripts

Recipe for a great script

“Do you ever find yourself typing the same set of
commands over and over to get a certain task done?
Do you ever find yourself clicking the same set of
buttons in the same sequence in the same wizard just
to complete some chore - and then have to repeat the
same process for, say, multiple computers or multiple
user accounts?”

• Create or change user/computer accounts
• Reset passwords
• Upload or download files via FTP
• Temp file/folder cleanups
• Execute SQL backups
• Get information about user/computer objects
• Watch print queues
• Email a user
• Install software
• .etc

Scripting. Why?

…allow for error handling
…know how to debug
…comment/document code
…declare variables (best practice)
…make your scripts as scaleable and generic as
possible
…be able to “Frankenscript”TM

Remember, there are lots of ways of doing the
same thing with code. Do what makes sense to you

Admin Scripting Skills

• VBScript requires no additional software to be
installed on older servers and workstations.
• VBScript is a runtime scripting language
loosely based off of VBA and VB
• You can build a GUI for your VBScripts using
HTA (Javascripts too)
• VBScript runs with less overhead, but it is not
as powerful or intuitive as PowerShell

Why VBScript?

• Variables – a “container” where you can store values
temporarily
• Constant – a variable used like an alias (non-changing value)
• Objects – a subset of predefined code which can allow access
to system level functions. You can use a variable to reference
an object by using ‘Set’
– Properties – read/writable attributes of a particular object
– Methods – actions that can be performed with an object
• Functions – reusable code that can return a value via the
calling command
• Subroutines – reusable code that can be executed to perform
a special task

VBScripts run as a .vbs or .vbe file http://goo.gl/KJ5op

Anatomy

There are two .exe’s which can run as the
scripting host:
• Wscript.exe: outputs messages to separate windows as
messages occur.
• Cscript.exe: outputs messages to the command-line
interface in succession.

Depending on how you are implementing your scripts, you
may choose to run one instead of the other.

Example: cscript.exe demo.vbs

Any time you wish to work with files, environment variables, Active
Object method and property
Directory, WMI, the Windows Shell, etc. you will need to “create” the
corresponding object in your code.

Dim objFSO, objFIle
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.GetFile(“c:windowswindowsupdate.log”)
wscript.echo objFile.DateLastModified

Demo

Anatomy

Variable/Constant a permanent valuesrepopulated during
Variables are temporarywith
Constants are variables containers that may be which cannot be reset
script execution with different values.
programmatically.

Dim strDescription
strDescription = “testing 1, 2, 3."
Const SpiceworldDescription = “awesome”
strDescription = “I think Spiceworld is hella ” _
& SpiceworldDescription
wscript.echo strDescription
Wscript.echo “That was “ & SpiceworldDescription

Demo

Anatomy

Functions are used for returning values back directly to the code which
Function
called them.
Here, we are passing a variable to a
Dim strFileName function (a file path)…

wscript.echo funGetLastModified(“c:windowswindowsupdate.log”)

Function funGetLastModified(strFilename)
Dim objFSO, objFIle
Set objFile = objFSO.GetFile(strFilename)
funGetLastModified = objFile.DateLastModified …which is returned back
End function to wscript.echo here.

Demo

Anatomy

Subroutine
Dim strFileDate
Call subGetLastModified(“c:windowswindowsupdate.log”)
wscript.echo strFileDate

Sub subGetLastModifed(strFilename)
Dim objFSO, objFIle
Set objFile = objFSO.GetFile(strFilename)
strFileDate = objFile.DateLastModified
End Sub

Demo

Subroutines are well suited for self-contained processes that don’t need to return values back to the
originating code. Use it to work with items, files, etc. that remain somewhat independent from the
rest of the script, such as displaying error messages.

Anatomy

• Typos/fat-fingering
• Invalid use of variable data
• Syntax problems
• Logic problems
• Etc.

How do we get around these problems?

• You should always expect your scripts to encounter
errors
• Anything encountered which isn’t expected is
considered an “error” to the scripting engine
• In these cases, you’ll want to force the script to
resume past errors and continue onward.

Use:
On Error Resume Next

Option Explicit
Dim Scott, objPerson
Dim Scott, objPerson
Set objPerson = CreateObject(“Scripting.PersonObject")
Set Scott = objPerson.MindControl(“Scott Brosnan")
objPerson = CreateObject(“Scripting.PersonObject")
On error resume next
Set Scott
Scott.walk=“through door”
objPerson.MindControl(“Scott Brosnan")
Scott.sing “Star Spangled Banner.wav”
Scott.walk “through front door”
Scott.echo “All done!”
Scott.sing “Star Spangled Banner.wav”
Scott.echo “All done!”

Mind control

Option Explicit
dim objFSO
set objFSO = CreateObject("Scripting.FileSystemObject")
objFSO.CopyFile "c:temptest.txt", "c:temptemp1"
MsgBox "Script finished."

If “test.txt” doesn’t exist on the computer running this script, the scripting host will produce
an error and terminate.

Now that your script can make it past its first error…

Let’s use this to our advantage by utilizing the ‘err’ object. It has a couple important
properties:

Err.number = provides numerical error
Err.description = sometimes provides more descriptive detail about error

„other code goes here
If err.number <> 0 then
Msgbox err.number & “ – “ & err.description
End If

Reading from a text file via vbscript
goes a bit like this:

1. Use the filesystem object to open a text file
2. Either read the entire contents of the file into a
variable, or move through each line to process
that line individually
3. Call a function or subroutine to do something
with the information in that variable

Option Explicit
Const ForReading = 1
Dim objFSO, sourcefile

Set sourcefile = objFSO.OpenTextFile("c:tempcomputers.txt",ForReading)

Do Until sourcefile.AtEndOfStream = True
wscript.echo sourcefile.readline
Loop

Set objFSO = nothing

In order to read from a text file, we need to state that we are going to
use a constant and the filesystem object.

Next, we are going to open the file using the filesystem object (known
as objFSO) by using the ‘OpenTextFile’ method.

If we are going to process each line, we will need to tell the script how
to handle it until the file reaches the end (using the AtEndOfStream
method).

Option Explicit
Const ForWriting = 2
Dim objFSO, logfile

Set Logfile = objFSO.OpenTextFile("c:templogfile.log", ForWriting, True)

Logfile.writeline("This is an entry in my logfile")

Logfile.close
Set objFSO = nothing

In order to write to a text file, we need to specify we are going to use
a constant and the filesystem object. Note the ‘ForWriting’ constant
(instead of ‘ForReading’).

Again, we are going to open the file using the filesystem object
(known as objFSO) and use the ‘OpenTextFile’ method.

The FileSystemobject grants us a ‘writeline’ method, enabling you to
write text directly to a file.

Option Explicit
Dim WshShell, objExecResults

Set WshShell = CreateObject("WScript.Shell")
Set objExecResults = WshShell.Exec("ping.exe 127.0.0.1")

wscript.echo objExecResults.StdOut.ReadAll

To read the output of a command line, we need to invoke the
‘wscript.shell’ object. This object allows us to execute a program
using the ‘exec’ method.

We are going to place the output of the execute method into
‘objExecResults.’

In order to see our output in a readable format, we’ll use the ‘ReadAll’
method to read the contents of objExecResults into a variable or
directly to the screen.

Methods Properties
• AppActivate • CurrentDirectory
• CreateShortcut • Environment
• Exec
• ExpandEnvironmentStrings • SpecialFolders
• LogEvent
• Popup
• RegDelete
• RegRead
• RegWrite
• Run
• SendKeys

Get sample usage and more details here: http://goo.gl/Rc3Z8

Wscript properties/methods

Methods Properties
• MapNetworkDrive • ComputerName
• EnumNetworkDrives • UserDomain
• RemoveNetworkDrive
• AddPrinterConnection • UserName
• AddWindowsPrinterConnection
• EnumPrinterConnections
• SetDefaultPrinter
• RemovePrinterConnection

Get sample usage and more details here: http://goo.gl/C9BT5

Wscript properties/methods

• WMI computer as the implementation of Web-based
Think of theis Microsoft’sdatabase, and the WMI classes at tables.
You Enterprise various WMI classes(WBEM) querying a SQL
will query the Management as if you were
• Every
database modern Windows computer has a localized
WMI repository
• Spiceworks gets a lot of its data from the WMI
repository
• WMI class examples:
Win32_logicaldisk, Win32_bios, Win32_Computer
System
• You can quickly query local or remote repositories
with VBScript, Powershell or Batch (etc.) scripts

To figure out how to query WMI via
VBScript (or other languages), you’ll need:
• Microsoft Scriptomatic 2.0
-or-
• WMIGen by Rob van der Woude

These are tools which can allow you
to generate specific code to import
into your own scripts.

Option Explicit
Dim objWMIService, strComputer, colItems
strComputer = "."

Set objWMIService = GetObject("winmgmts:" & strComputer & "rootCIMV2")
Set colItems = objWMIService.ExecQuery("SELECT * FROM Win32_OperatingSystem", "WQL")

For Each objItem In colItems
WScript.Echo "BootDevice: " & objItem.BootDevice
WScript.Echo "Caption: " & objItem.Caption
WScript.Echo "Service Pack: " & objItem.ServicePackMajorVersion
Next

Instead of creating an object, we are getting an object, since this is
already active. In this case, we are getting an object from the
rootCIMV2 namespace…

Next we are going to place the results of a WQL query into the
colItems (collection) object.

This particular script will return the local or remote computer’s boot
device, OS name and service pack level.

Option Explicit
Dim objWMIService, strComputer, colItems
strComputer = "."

Set colItems = objWMIService.ExecQuery("SELECT * FROM Win32_DiskDrive", "WQL")

WScript.Echo "Caption: " & objItem.Caption
Wscript.echo "Size: " & objItem.Size
Next

Here, we are querying the Win32_DiskDrive class…

Since the results are placed into a collection (colItems), then we must
loop through it, even if there might be only one item in the collection.

Option Explicit
Dim strComputer, objWMIService, colItems, strIPAddress

strComputer = "."
on error resume next

Set colItems = objWMIService.ExecQuery("SELECT * FROM
Win32_NetworkAdapterConfiguration", "WQL")

WScript.Echo "Description: " & objItem.Description
strIPAddress = Join(objItem.IPAddress, ",")
WScript.Echo "IPAddress: " & strIPAddress
Next

Notice the ‘Join’ function. Some adapters have more than one IP
address.

• Active Directory is a database of fields and
values, think of a user/computer object as a
record
• When querying AD, you should utilize filters to
make your query more efficient
• You need to specify the attributes you wish to
report against
(pwdLastset, samAccountName,DN)
• You should try to isolate your queries to the OU
structure where your results are located

Tools you will need

• Get AD Object Attributes VBScript http://goo.gl/csLFD
• ADExplorer (SysInternals) – find your attributes
• ADUC MMC – build your filter

The strFilter variable allows you to build your Active Directory filter. You
The strAttributes variable should be populated with the fields you would
can use the Microsoft ADUC to build this query and paste into this
like the script to report back. Things like user name, computer
variable.
name, account creation date, etc. can be returned…

There are MANY ways to get
Active Directory data from
your network.

Do what works for you…

• HTA (HyperText Application) is
essentially a web page with full system
privileges - think of HTML + VBScript
• If you can write HTML, you can make an
HTA
• Great for single-task functions (reset a
password)

<html>
<head>
<title>HTA Helpomatic</title>

<HTA:APPLICATION
ID="objHTAHelpomatic"
APPLICATIONNAME="HTAHelpomatic"
SCROLL="yes"
SINGLEINSTANCE="yes"
WINDOWSTATE="maximize"
>
</head>

<SCRIPT Language="VBScript">
</SCRIPT>
<body>Well, this is boring, huh?</body>
</html>

Tool Link (Case-sensitive)
Microsoft Scriptomatic v2.0 http://goo.gl/eL98u
Microsoft HTA-Helpomatic http://goo.gl/cCvDM
Rob van der Woude’s WMIGen http://goo.gl/jBNkv
PSPad Editor http://www.pspad.com
Notepad++ Editor http://notepad-plus-plus.org/
SysInternals’ ADExplorer http://goo.gl/hzX48

Resource Link (Case-sensitive)
Microsoft VBScript reference http://goo.gl/uDiFd
WScript Host object reference http://goo.gl/uJHWn
Get AD Object Attributes Script http://goo.gl/csLFD
Microsoft Script Center http://goo.gl/9BcyD
All built-in VBScript Functions http://goo.gl/iXza8

Scripting as a Second Language

Scripting as a Second Language

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