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== Useful Sites ==
#REDIRECT [[:Category:PowerShell]]
Subject specific useful links are listed in the sections below
* [http://www.microsoft.com/windowsserver2003/technologies/management/powershell/download.mspx Windows PowerShell V1]
* [http://support.microsoft.com/kb/968929 Windows PowerShell V2]
* http://powershell.com/cs/ - Good all-round help
* http://technet.microsoft.com/en-us/library/bb978526.aspx - TechNet!
 
== Installed Version ==
To check the installed version see the registry key <code>HKLM\Software\Microsoft\PowerShell\1</code>, which will have the following values of interest...
{|cellpadding="1" cellspacing="0" border="1"
|- style="background-color:#bbddff;"
! Value                !! Data                                !! Meaning
|-
|<code> Install </code> || <number>                            || Version number
|-
|<code> PID </code>    || <code>89383-100-0001260-04309</code> || RTM
|-
|<code> PID </code>    || <code>89393-100-0001260-00301</code> || RC2
|}
 
 
== Variables ==
Powershell is all about manipulating objects, and its variables are all essentially the same, not being specifically defined as an object, string, integer, etc. Which is normally useful, however sometimes you need to force a variable to contain a data type. Using a prefix of [type] achieves this...
* <code> [string]$result = $PingResult.Status </code>
 
{|cellpadding="1" cellspacing="0" border="1"
|- style="background-color:#bbddff;"
! Notation                      !! Data Type
|-
|<code> [datetime] </code>      || Date or time
|-
|<code> [string] </code> || String of characters
|-
|<code> [char]  </code> || Single character
|-
|<code> [double] </code> || Double-precision floating number
|-
|<code> [single] </code> || Single-precision floating number
|-
|<code> [int] </code> || 32-bit integer
|-
|<code> [wmi] </code> || Windows Management Instrumentation (WMI) instance or collection
|-
|<code> [adsi] </code> || Active Directory Services object
|-
|<code> [wmiclass] </code> || WMI class
|-
|<code> [Boolean] </code> || True or False value
|}
 
 
== Credentials ==
When running commands that require a connection to a remote machine its useful to be able to store a user/pass combination so that you aren't repeatedly prompted every time you run a command.  Create a credential object, then supply that in place of a username in a command
 
<pre>
PS H:\> $cred = Get-Credential
 
cmdlet Get-Credential at command pipeline position 1
Supply values for the following parameters:
Credential
PS H:\> Get-WMIObject -query "SELECT * FROM Win32_OperatingSystem" -credential $cred -computer 159.104.224.167
 
SystemDirectory : C:\WINDOWS\system32
Organization    : TF
BuildNumber    : 3790
RegisteredUser  : TF
SerialNumber    : 69712-640-3560061-45009
Version        : 5.2.3790
</pre>
 
 
== WMI ==
 
Cmdlet for using WMI via PowerShell is '''Get-WMIObject''', which has an alias of '''gwmi''', for example...
 
<pre>
PS H:\> Get-WMIObject -query "Select * from Win32_OperatingSystem"
 
SystemDirectory : C:\WINDOWS\system32
Organization    :
BuildNumber    : 2600
RegisteredUser  : TF
SerialNumber    : 76487-OEM-0011903-00102
Version        : 5.1.2600
 
PS H:\> Get-WMIObject -query "SELECT * FROM Win32_UTCTime"
 
__GENUS          : 2
__CLASS          : Win32_UTCTime
__SUPERCLASS    : Win32_CurrentTime
__DYNASTY        : Win32_CurrentTime
__RELPATH        : Win32_UTCTime=@
__PROPERTY_COUNT : 10
__DERIVATION    : {Win32_CurrentTime}
__SERVER        : L-0STRUTTS1
__NAMESPACE      : root\cimv2
__PATH          : \\L-0STRUTTS1\root\cimv2:Win32_UTCTime=@
Day              : 27
DayOfWeek        : 4
Hour            : 10
Milliseconds    :
Minute          : 0
Month            : 8
Quarter          : 3
Second          : 1
WeekInMonth      : 5
Year            : 2009
 
PS H:\> Get-WMIObject -query "Select * from Win32_OperatingSystem" -credential sysmgr -computer ukpgemon2
 
SystemDirectory : C:\WINDOWS\system32
Organization    : Thomson Financial
BuildNumber    : 3790
RegisteredUser  : Dell Image Rev 1
SerialNumber    : 69712-640-3560061-45321
Version        : 5.2.3790
 
PS H:\> Get-WMIObject -query "Select * from Win32_userAccount WHERE Domain = 'OCM-WCS1' AND Name = 'pptp_ypos'" -credential administrator -computer 159.104.224.167
AccountType : 512
Caption    : OCM-WCS1\pptp_ypos
Domain      : OCM-WCS1
SID        : S-1-5-21-2453442427-2400495818-1845097998-1073
FullName    : Ypos-Consulting GmbH
Name        : pptp_ypos
</pre>
 
 
=== Find Classes and Properties ===
 
In order to find the correct class use...
<pre>
Get-WMIObject -list -credential $cred -computer 159.104.224.167 | Select-String -InputObject {$_.Name} Win32*
</pre>
 
To then see all the properties of a class use (doesn't work on remote machines (access denied) - this is a known bug in Power Shell v1)...
<pre>
Get-WMIObject Win32_BIOS | Format-List *
</pre>
 
[http://technet.microsoft.com/en-gb/magazine/2009.02.windowspowershell.aspx TechNet article: Windows PowerShell Best Inventory Tool Ever!]
 
== Network ==
=== Ping ===
<pre>
PS H:\> $objPing = New-Object system.Net.NetworkInformation.Ping
PS H:\> $objPing.Send('127.0.0.1')
 
Status        : Success
Address      : 127.0.0.1
RoundtripTime : 0
Options      : System.Net.NetworkInformation.PingOptions
Buffer        : {97, 98, 99, 100...}
</pre>
 
=== Name/Address Resolution ===
'''IP to Name'''
* Be aware, where no name can be found, the call throws an exception.  If assigning result to a variable, then it seems to return the local hostname, which is odd.
<pre>
PS H:\> [System.Net.Dns]::GetHostbyAddress("159.104.31.83")
 
HostName                                Aliases                                AddressList
--------                                -------                                -----------
L-STRUTTS1                              {}                                      {159.104.31.83}
</pre>
 
'''Name to IP'''
<pre>
PS H:\> [System.Net.Dns]::GetHostAddresses("l-strutts1")
 
Address          : 1394567327
AddressFamily    : InterNetwork
ScopeId          :
IsIPv6Multicast  : False
IsIPv6LinkLocal  : False
IsIPv6SiteLocal  : False
IPAddressToString : 159.104.31.83
</pre>
 
== MySQL ==
=== Connect ===
 
<pre>
function ConnectMySQL([string]$user,[string]$pass,[string]$MySQLHost,[string]$database) {
  # Load MySQL .NET Connector Objects
  [void][system.reflection.Assembly]::LoadWithPartialName("MySql.Data")
 
  # Open Connection
  $connStr = "server=" + $MySQLHost + ";port=3306;uid=" + $user + ";pwd=" + $pass + ";database="+$database+";Pooling=FALSE"
  $conn = New-Object MySql.Data.MySqlClient.MySqlConnection($connStr)
  $conn.Open()
  return $conn
}
 
function DisconnectMySQL($conn) {
  $conn.Close()
}
 
# So, for example...
 
# Connection Variables
$user = 'myuser'
$pass = 'mypass'
$database = 'mydatabase'
$MySQLHost = 'database.server.com'
 
# Connect to MySQL Database
$conn = ConnectMySQL $user $pass $MySQLHost $database
 
</pre>
 
=== Commands ===
All database operations are done through methods of the <code> MySqlCommand </code> object, the two methods of main interest are...
* '''ExecuteNonQuery''' - Used for queries that don't return any real information, such as an INSERT, UPDATE, or DELETE.
* '''ExecuteReader''' - Used for normal queries that return multiple values.  Results need to be received into <code> MySqlDataReader </code> object.
* '''ExecuteScalar''' - Used for normal queries that return a single.  The result needs to be received into a variable.
 
'''Non-Query'''
<pre>
function ExecuteMySQLNonQuery($conn, [string]$query) {
  $command = $conn.CreateCommand()                  # Create command object
  $command.CommandText = $query                    # Load query into object
  $RowsInserted = $command.ExecuteNonQuery()        # Execute command
  $command.Dispose()                                # Dispose of command object
  if ($RowsInserted) {
    return $RowInserted
  } else {
    return $false
  }
}
 
# So, to insert records into a table
$query = "INSERT INTO test (id, name, age) VALUES (1, 'Joe', 33)"
$Rows = ExecuteMySQLNonQuery $conn $query
Write-Host $Rows " inserted into database"
</pre>
 
'''Reader Query'''
In theory, this should work, but it doesn't seem to for me.  There's something wrong with the <code>while ($results.Read())</code>, in that you end up displaying the last row returned by the SQL query multiple times.  Suspect its due to the way that a Reader object only seems to hold a result temporarily.
<pre>
$query = "SELECT * FROM subnets;"
$cmd = $connMySQL.CreateCommand()
$cmd.CommandText = $query
$results = $cmd.ExecuteReader()
$cmd.Dispose()
while ($results.Read()) {
  for ($i= 0; $i -lt $reader.FieldCount; $i++) {
      write-output $reader.GetValue($i).ToString()
  }
}
</pre>
 
Instead, this approach seems to work more reliably.  By loading the data into a dataset, it becomes available for offline manipulation and isn't reliant on the database once the data is loaded in.
<pre>
function ExecuteMySQLQuery([string]$query) {
  # NonQuery - Insert/Update/Delete query where no return data is required
  $cmd = New-Object MySql.Data.MySqlClient.MySqlCommand($query, $connMySQL)    # Create SQL command
  $dataAdapter = New-Object MySql.Data.MySqlClient.MySqlDataAdapter($cmd)      # Create data adapter from query command
  $dataSet = New-Object System.Data.DataSet                                    # Create dataset
  $recordCount = $dataAdapter.Fill($dataSet, "data")                          # Fill dataset from data adapter, with name "data"             
  $cmd.Dispose()
  return $dataSet.Tables["data"]
}
 
# So, to produce a table of results from a query...
$query = "SELECT * FROM subnets;"
ExecuteMySQLQuery $query | Format-Table
'''Scalar Query'''
 
'''Other'''
<pre>
$cmd = New-Object MySql.Data.MySqlClient.MySqlCommand("USE $database", $conn)
</pre>
 
== Exceptions and Error Handling ==
* http://huddledmasses.org/trap-exception-in-powershell/ - Exception trapping
* http://www.pluralsight.com/community/blogs/keith/archive/2007/01/22/45814.aspx - Error handling
 
To control how a script behaves as a result of an exception, modify the <code> $ErrorActionPreference </code> variable, if required.
 
{|cellpadding="1" cellspacing="0" border="1"
|- style="background-color:#bbddff;"
! Value            !! Effect
|-
| Continue          || [Default] Outputs error, but keeps processing
|-
| SilentlyContinue  || No output and it keeps going
|-
| Inquire          || Prompt user for action
|-
| Stop              || Outputs error and halts processing
|}
 
 
=== Basic Error Catcher ===
 
If you know where the error is likely to occur, then just place an error catcher immediately after it...
<pre>
if (-not $?) {
    # Handle error here
  }
</pre>
 
[[Category:PowerShell]]
[[Category:WMI]]
[[Category:MySQL]]

Latest revision as of 15:37, 4 October 2016

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