PowerShell Notes

1.  概要

- PowerShell 是cmdlet（command-let）的指令集合，类似unix的bash。

- IDE: Windows PowerShell ISE，不区分大小写，可以用命令行get-help获取帮助

- 以.NET为基础，向前兼容WSH，可以使用现有的COM技术，也可以直接访问.NET类库(如：[io.path]::GetDirectoryName($MyInvocation.InvocationName))，可以与windows系的相关软件互动（如：Excel， Exchange Server等）。

- wiki上的范例

 #1 - 获取所有命令[4]：
 PS> Get-Command
 #2 - 查看Get-Command命令的用法[5]：
 PS> Get-Help Get-Command
 #3 - 停止所有目前執行中的以"p"字元開頭命名的程式：
 PS> get-process p* | stop-process
 #4 - 停止所有目前執行中的所有使用大於1000MB記憶體的程式：
 PS> get-process | where { $_.WS -gt 1000MB } | stop-process
 #5 - 計算一個目錄下檔案內的位元組大小：
 PS> get-childitem | measure-object -property length -sum
 #6 - 等待一個叫做"notepad"的程式執行結束：
 PS> $processToWatch = get-process notepad
 PS> $processToWatch.WaitForExit()
 #7 - 將"hello, world!"字串轉為英文大寫字元，成為"HELLO, WORLD!"：
 PS> "hello, world!".ToUpper()
 #8 - 在字串"string"的第1個字元後插入字串"ABC"，成為"sABCtring"：
 PS> "string".Insert(1, "ABC")
 #9 - 訂閱一個指定的RSS Feed並顯示它最近8個主題：
 PS> $rssUrl = "http://blogs.msdn.com/powershell/rss.aspx"
 PS> $blog = [xml](new-object System.Net.WebClient).DownloadString($rssUrl)
 PS> $blog.rss.channel.item | select title -first 8
 #10 - 把"$UserProfile"設定成數值"UserProfile"的環境變數：
 PS> $UserProfile = $env:UserProfile

2.  一段PS脚本的解析

 $status = @{1 = "L"; 2 = "R"; 4 = "W"; 8 = "M"}
 $value = 14
 $statutext = ($status.Keys | where { $_ -band $value } | foreach { $status.Get_Item($_) } | sort) -join ""
 $expecting = ($expecting.GetEnumerator() | sort) -join ""

- $_ 代表循环体内的值，$status中的key哪些包含在$value中，以上代码段中当$value=14时，$status.Keys | where { $_ -band $value }的结果为 {2，4，8}

- 操作符-band 表示bit and； -join 作用是把数组连接成字符串，可以通过get-help about_join获得具体使用方法

- 操作符 | 为pipe line，如： command1 | command2 | command3，执行顺序为 command1 -〉 command2 -〉 command3

#参考文档 1

3.  about_Splatting

TOPIC
    about_Splatting

SHORT DESCRIPTION
    Describes how to use splatting to pass parameters to commands
    in Windows PowerShell.

LONG DESCRIPTION
    [This topic was contributed by Rohn Edwards of Gulfport,
     Mississippi, a system administrator and the winner
     of the Advanced Division of the 2012 Scripting Games.
     Revised for Windows PowerShell 3.0.]

    Splatting is a method of passing a collection of parameter
    values to a command as unit. Windows PowerShell associates
    each value in the collection with a command parameter.
    Splatted parameter values are stored in named splatting
    variables, which look like standard variables, but begin with
    an At symbol (@) instead of a dollar sign ($). The At symbol
    tells Windows PowerShell that you are passing a collection of
    values, instead of a single value.

    Splatting makes your commands shorter and easier to read. You
    can re-use the splatting values in different command calls and
    use splatting to pass parameter values from the $PSBoundParameters
    automatic variable to other scripts and functions.

    Beginning in Windows PowerShell 3.0, you can also use splatting
    to represent all parameters of a command.

SYNTAX

    <CommandName> <optional parameters> @<HashTable> <optional parameters>

    <CommandName> <optional parameters> @<Array> <optional parameters>

    To provide parameter values for positional parameters, in which
    parameter names are not required, use the array syntax. To provide
    parameter name and value pairs, use the hash table syntax. The
    splatted value can appear anywhere in the parameter list.

    When splatting, you do not need to use a hash table or an array to
    pass all parameters. You may pass some parameters by using splatting
    and pass others by position or by parameter name. Also, you can splat
    multiple objects in a single command just so you pass no more than one
    value for each parameter.

 SPLATTING WITH HASH TABLES
    Use a hash table to splat parameter name and value pairs. You can use
    this format for all parameter types, including positional and named
    parameters and switch parameters.

    The following examples compare two Copy-Item commands that copy the
    Test.txt file to the Test2.txt file in the same directory. 

    The first example uses the traditional format in which parameter names
    are included.

        Copy-Item -Path "test.txt" -Destination "test2.txt" -WhatIf

    The second example uses hash table splatting. The first command creates
    a hash table of parameter-name and parameter-value pairs and stores it
    in the $HashArguments variable. The second command uses the $HashArguments
    variable in a command with splatting. The At symbol (@HashArguments)
    replaces the dollar sign ($HashArguments) in the command.

    To provide a value for the WhatIf switch parameter, use $True or $False. 

       PS C:\>$HashArguments = @{ Path = "test.txt"; Destination = "test2.txt"; WhatIf = $true }
       PS C:\>Copy-Item @HashArguments

    Note: In the first command, the At symbol (@) indicates a hash table, not
          a splatted value. The syntax for hash tables in Windows PowerShell is:
          @{ <name>=<value>; <name>=<value>; …} 

 SPLATTING WITH ARRAYS
    Use an array to splat values for positional parameters, which do not require
    parameter names. The values must be in position-number order in the array.

    The following examples compare two Copy-Item commands that copy the Test.txt
    file to the Test2.txt file in the same directory. 

    The first example uses the traditional format in which parameter names are
    omitted. The parameter values appear in position order in the command.

        Copy-Item "test.txt" "test2.txt" -WhatIf

    The second example uses array splatting. The first command creates an array
    of the parameter values and stores it in the $ArrayArguments variable. The
    values are in position order in the array. The second command uses the
    $ArrayArguments variable in a command in splatting. The At symbol
    (@ArrayArguments) replaces the dollar sign ($ArrayArguments) in the command.

        PS C:\>$ArrayArguments = "test.txt", "test2.txt"
        PS C:\>Copy-Item @ArrayArguments -WhatIf

 EXAMPLES

    This example shows how to re-use splatted values in different commands.
    The commands in this example use the Write-Host cmdlet to write messages
    to the host program console. It uses splatting to specify the foreground
    and background colors.

    To change the colors of all commands, just change the value of the $Colors
    variable.

    The first command creates a hash table of parameter names and values and
    stores the hash table in the $Colors variable.

               $Colors = @{ForegroundColor = "black"
                           BackgroundColor = "white"}

    The second and third commands use the $Colors variable for splatting in a
    Write-Host command. To use the $Colors variable, replace the dollar sign
    ($Colors) with an At symbol (@Colors).

               # Write a message with the colors in $Colors
               Write-Host "This is a test." @Colors

               # Write second message with same colors.
               # The position of splatted hash table does not matter.
               Write-Host @Colors "This is another test."

    This example shows how to forward their parameters to other commands by
    using splatting and the $PSBoundParameters automatic variable. 

    The $PSBoundParameters automatic variable is a dictionary
    (System.Collections.Generic.Dictionary) that contains all of the
    parameter names and values that are used when a script or function
    is run. 

    In the following example, we use the $PSBoundParameters variable to
    forward the parameters values passed to a script or function from Test2
    function to the Test1 function. Both calls to the Test1 function from
    Test2 use splatting.

              function Test1
              {
                   param($a, $b, $c)

                   $a
                   $b
                   $c
               }              

              function Test2
              {
                   param($a, $b, $c)

                   # Call the Test1 function with $a, $b, and $c.
                   Test1 @PsBoundParameters

                   # Call the Test1 function with $b and $c, but not with $a
                   $LimitedParameters = $PSBoundParameters
                   $LimitedParameters.Remove("a") | Out-Null
                   Test1 @LimitedParameters
               }

               PS C:\> Test2 -a 1 -b 2 -c 3
               1
               2
               3
               2
               3

 SPLATTING COMMAND PARAMETERS
    You can use splatting to represent the parameters of
    a command. This technique is useful when you are creating
    a proxy function, that is, a function that calls another
    command. This feature is introduced in Windows PowerShell 3.0.

    To splat the parameters of a command, use @Args to represent
    the command parameters. This technique is easier than
    enumerating command parameters and it works without revision
    even if the parameters of the called command change.

    The feature uses the $Args automatic variable, which contains
    all unassigned parameter values.

    For example, the following function calls the Get-Process
    cmdlet. In this function, @Args represents all of the parameters
    of the Get-Process cmdlet.

        function Get-MyProcess { Get-Process @Args }

    When you use the Get-MyProcess function, all unassigned
    parameters and parameter values are passed to @Args, as
    shown in the following commands.

        PS C:\> Get-MyProcess -Name PowerShell  

        Handles  NPM(K)    PM(K)      WS(K) VM(M)   CPU(s)     Id ProcessName
        -------  ------    -----      ----- -----   ------     -- -----------
            463      46   225484     237196   719    15.86   3228 powershell

        PS C:\> Get-MyProcess -Name PowerShell_Ise -FileVersionInfo 

        ProductVersion   FileVersion      FileName
        --------------   -----------      --------
        6.2.9200.16384   6.2.9200.1638... C:\Windows\system32\WindowsPowerShell\v1.0\PowerShell_ISE.exe

    You can use @Args in a function that has explicitly
    declared parameters. You can use it more than once in
    a function, but all parameters that you enter are passed
    to all instances of @Args, as shown in the following
    example.

        function Get-MyCommand
        {
            Param ([switch]$P, [switch]$C)
            if ($P) { Get-Process @Args }
            if ($C) { Get-Command @Args }
        }        

        PS C:\> Get-MyCommand -P -C -Name PowerShell

        Handles  NPM(K)    PM(K)      WS(K) VM(M)   CPU(s)     Id ProcessName
        -------  ------    -----      ----- -----   ------     -- -----------
            408      28    75568      83176   620     1.33   1692 powershell

        Path               : C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
        Extension          : .exe
        Definition         : C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
        Visibility         : Public
        OutputType         : {System.String}
        Name               : powershell.exe
        CommandType        : Application
        ModuleName         :
        Module             :
        RemotingCapability : PowerShell
        Parameters         :
        ParameterSets      :
        HelpUri            :
        FileVersionInfo    : File:             C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe

SEE ALSO
    about_Arrays
    about_Automatic_Variables
    about_Hash_Tables
    about_Parameters

$props = @{
    From = $FROM_EMAIL_ADDRESS
    To= $to
    Subject = $subject
    Body = $message
    SmtpServer = $EMAIL_SERVER
}

If($cc){$props.Add("CC",$cc)}

Send-MailMessage @props

Hashtable操作

4. launch VBA script from powershell

==============Powershell script=======================
$xl = new-object -comobject Excel.Application
$source_wb = $xl.workbooks.open("myExcel.xls")
$xl.visible=$false
$param = "myMethod myParams1 myParams2"
$type=$xl.GetType()

$ret=$type.InvokeMember("Run",[Reflection.BindingFlags]::InvokeMethod,$null,$xl,$param)
$xl.Quit()
[System.Runtime.Interopservices.Marshal]::ReleaseComObject($xl)
Remove-Variable xl

==============VBA script=======================
Sub myMethod(ByVal p1 As String, ByVal p2 As String)
  'TODO sth.
End Sub

5. 获取当前脚本运行的路径

把以下脚本放到function里面，否则Path为null

Split-Path $script:MyInvocation.MyCommand.Path

#to make this snippet work, it should be named as a powershell file
# e.g. save it as D:\Scripts\get-location1.ps1

function Get-ScriptDirectory
{
    #Split-Path $script:MyInvocation.MyCommand.Path
    return $script:MyInvocation.MyCommand.Path
}

"immediate func call"
$xxx = Get-ScriptDirectory
echo $xxx

6. here-string

 $x = @"
 "
 Curiouser
 and
 curiouser
 !
 "
 "@

7.