01.理解powershell的特性

001.输出是对象

可以使用Get-Member查看输出的对象有那些成员，比如

Get-Process | Get-Member

   TypeName: System.Diagnostics.Process

Name                       MemberType     Definition
----                       ----------     ----------
Handles                    AliasProperty  Handles = Handlecount
Name                       AliasProperty  Name = ProcessName
NPM                        AliasProperty  NPM = NonpagedSystemMemorySize64
PM                         AliasProperty  PM = PagedMemorySize64
SI                         AliasProperty  SI = SessionId
VM                         AliasProperty  VM = VirtualMemorySize64
WS                         AliasProperty  WS = WorkingSet64
Parent                     CodeProperty   System.Object Parent{get=GetParentProcess;}
Disposed                   Event          System.EventHandler Disposed(System.Object, System.EventArgs)
ErrorDataReceived          Event          System.Diagnostics.DataReceivedEventHandler ErrorDataReceived(System.Object, System.Diagnostics.DataReceivedEventArgs)       Exited                     Event          System.EventHandler Exited(System.Object, System.EventArgs)
OutputDataReceived         Event          System.Diagnostics.DataReceivedEventHandler OutputDataReceived(System.Object, System.Diagnostics.DataReceivedEventArgs)      BeginErrorReadLine         Method         void BeginErrorReadLine()
BeginOutputReadLine        Method         void BeginOutputReadLine()
CancelErrorRead            Method         void CancelErrorRead()
CancelOutputRead           Method         void CancelOutputRead()
Close                      Method         void Close()
CloseMainWindow            Method         bool CloseMainWindow()
Dispose                    Method         void Dispose(), void IDisposable.Dispose()
Equals                     Method         bool Equals(System.Object obj)
GetHashCode                Method         int GetHashCode()
GetLifetimeService         Method         System.Object GetLifetimeService()
GetType                    Method         type GetType()
InitializeLifetimeService  Method         System.Object InitializeLifetimeService()
Kill                       Method         void Kill(), void Kill(bool entireProcessTree)
Refresh                    Method         void Refresh()
Start                      Method         bool Start()
ToString                   Method         string ToString()
WaitForExit                Method         void WaitForExit(), bool WaitForExit(int milliseconds)
WaitForInputIdle           Method         bool WaitForInputIdle(), bool WaitForInputIdle(int milliseconds)
__NounName                 NoteProperty   string __NounName=Process
BasePriority               Property       int BasePriority {get;}
Container                  Property       System.ComponentModel.IContainer Container {get;}
EnableRaisingEvents        Property       bool EnableRaisingEvents {get;set;}
ExitCode                   Property       int ExitCode {get;}
ExitTime                   Property       datetime ExitTime {get;}
Handle                     Property       System.IntPtr Handle {get;}
HandleCount                Property       int HandleCount {get;}
HasExited                  Property       bool HasExited {get;}
Id                         Property       int Id {get;}
MachineName                Property       string MachineName {get;}
MainModule                 Property       System.Diagnostics.ProcessModule MainModule {get;}
MainWindowHandle           Property       System.IntPtr MainWindowHandle {get;}
MainWindowTitle            Property       string MainWindowTitle {get;}
MaxWorkingSet              Property       System.IntPtr MaxWorkingSet {get;set;}
MinWorkingSet              Property       System.IntPtr MinWorkingSet {get;set;}
Modules                    Property       System.Diagnostics.ProcessModuleCollection Modules {get;}
NonpagedSystemMemorySize   Property       int NonpagedSystemMemorySize {get;}
NonpagedSystemMemorySize64 Property       long NonpagedSystemMemorySize64 {get;}
PagedMemorySize            Property       int PagedMemorySize {get;}
PagedMemorySize64          Property       long PagedMemorySize64 {get;}
PagedSystemMemorySize      Property       int PagedSystemMemorySize {get;}
PagedSystemMemorySize64    Property       long PagedSystemMemorySize64 {get;}
PeakPagedMemorySize        Property       int PeakPagedMemorySize {get;}
PeakPagedMemorySize64      Property       long PeakPagedMemorySize64 {get;}
PeakVirtualMemorySize      Property       int PeakVirtualMemorySize {get;}
PeakVirtualMemorySize64    Property       long PeakVirtualMemorySize64 {get;}
PeakWorkingSet             Property       int PeakWorkingSet {get;}
PeakWorkingSet64           Property       long PeakWorkingSet64 {get;}
PriorityBoostEnabled       Property       bool PriorityBoostEnabled {get;set;}
PriorityClass              Property       System.Diagnostics.ProcessPriorityClass PriorityClass {get;set;}
PrivateMemorySize          Property       int PrivateMemorySize {get;}
PrivateMemorySize64        Property       long PrivateMemorySize64 {get;}
PrivilegedProcessorTime    Property       timespan PrivilegedProcessorTime {get;}
ProcessName                Property       string ProcessName {get;}
ProcessorAffinity          Property       System.IntPtr ProcessorAffinity {get;set;}
Responding                 Property       bool Responding {get;}
SafeHandle                 Property       Microsoft.Win32.SafeHandles.SafeProcessHandle SafeHandle {get;}
SessionId                  Property       int SessionId {get;}
Site                       Property       System.ComponentModel.ISite Site {get;set;}
StandardError              Property       System.IO.StreamReader StandardError {get;}
StandardInput              Property       System.IO.StreamWriter StandardInput {get;}
StandardOutput             Property       System.IO.StreamReader StandardOutput {get;}
StartInfo                  Property       System.Diagnostics.ProcessStartInfo StartInfo {get;set;}
StartTime                  Property       datetime StartTime {get;}
SynchronizingObject        Property       System.ComponentModel.ISynchronizeInvoke SynchronizingObject {get;set;}
Threads                    Property       System.Diagnostics.ProcessThreadCollection Threads {get;}
TotalProcessorTime         Property       timespan TotalProcessorTime {get;}
UserProcessorTime          Property       timespan UserProcessorTime {get;}
VirtualMemorySize          Property       int VirtualMemorySize {get;}
VirtualMemorySize64        Property       long VirtualMemorySize64 {get;}
WorkingSet                 Property       int WorkingSet {get;}
WorkingSet64               Property       long WorkingSet64 {get;}
PSConfiguration            PropertySet    PSConfiguration {Name, Id, PriorityClass, FileVersion}
PSResources                PropertySet    PSResources {Name, Id, Handlecount, WorkingSet, NonPagedMemorySize, PagedMemorySize, PrivateMemorySize, VirtualMemorySize, … Company                    ScriptProperty System.Object Company {get=$this.Mainmodule.FileVersionInfo.CompanyName;}
CPU                        ScriptProperty System.Object CPU {get=$this.TotalProcessorTime.TotalSeconds;}
Description                ScriptProperty System.Object Description {get=$this.Mainmodule.FileVersionInfo.FileDescription;}
FileVersion                ScriptProperty System.Object FileVersion {get=$this.Mainmodule.FileVersionInfo.FileVersion;}
Path                       ScriptProperty System.Object Path {get=$this.Mainmodule.FileName;}
Product                    ScriptProperty System.Object Product {get=$this.Mainmodule.FileVersionInfo.ProductName;}
ProductVersion             ScriptProperty System.Object ProductVersion {get=$this.Mainmodule.FileVersionInfo.ProductVersion;}

002.命令家族可扩展

不同于cmd，你编写的的powershell脚本也可以被powershell识别。可以用Get-Help查看你写的帮助文档。就和使用官方自带的cmdlet没什么区别。

003.powershell处理控制台输入和显示

powershell自己有一套机制控制控制台输出。对所有的cmdlet具有高度一致性。

比如命令行解析，不需要你自己去写了，powershell自带一套很方便的解析机制。

输出格式化也是，自带一套解析机制

比如传统shell不同命令行工具的打印帮助的参数可能不一样，有的是/?有的是-?，但是在powershell里面，所有cmdlet统一是-？.

当在powershell中运行图形程序的时候，只有当接受数输入的或者应用程序有返回的时候powershell才进行干涉。不会影响应用程序的内部工作方式。

02.理解powershell的命名

001.cmdlet是动词-名词的构成形式

方便记忆命令，并且很容易从名字了解命令的作用。

比如说只要记10个动词和10个名字（20个单词的记忆量），就可以组成100个命令了。

可以使用Get-Command分别查询有相关动词或名词的命令

PS> Get-Command -Verb Get

CommandType     Name                            Definition
-----------     ----                            ----------
Cmdlet          Get-Acl                         Get-Acl [[-Path] <String[]>]...
Cmdlet          Get-Alias                       Get-Alias [[-Name] <String[]...
Cmdlet          Get-AuthenticodeSignature       Get-AuthenticodeSignature [-...
Cmdlet          Get-ChildItem                   Get-ChildItem [[-Path] <Stri...
...


PS> Get-Command -Noun Service

CommandType     Name                            Definition
-----------     ----                            ----------
Cmdlet          Get-Service                     Get-Service [[-Name] <String...
Cmdlet          New-Service                     New-Service [-Name] <String>...
Cmdlet          Restart-Service                 Restart-Service [-Name] <Str...
Cmdlet          Resume-Service                  Resume-Service [-Name] <Stri...
Cmdlet          Set-Service                     Set-Service [-Name] <String>...
Cmdlet          Start-Service                   Start-Service [-Name] <Strin...
Cmdlet          Stop-Service                    Stop-Service [-Name] <String...
Cmdlet          Suspend-Service                 Suspend-Service [-Name] <Str...
...

002.cmdlets 使用标准化参数

powershell自带命令行参数解析，定义变量接受参数，会自动把-开头的参数导入变量。

所以在powershell中使用命令行参数，只要定义变量，然后使用就可以了。

有一些参数是所有cmdlet共用的，比如WhatIf, Confirm, Verbose, Debug, Warn, ErrorAction, ErrorVariable, OutVariable, and OutBuffer

推荐使用标准的参数名字，编写脚本的时候参考powershell自带的cmdlet命名就好了。比如 Force, Exclude, Include, PassThru, Path, and CaseSensitive.

03.使用已经熟悉的命令名

powershell支持别名，并且已经内置了一些别名，这样其他shell的使用者可以用他们熟悉的命令名了，虽然部分powershell的命令虽然名字一样，功能有差别。下面是一些支持的cmd和unix命令别名

适用Get-Aliascmdlet可以通过别名获取命令在powershell中的真名。

例子：

PS> Get-Alias cls

CommandType     Name                               Version    Source
-----------     ----                               -------    ------
Alias           cls -> Clear-Host

001.解释标准别名

之前描述的是为了兼容其他shell的命令别名，powershell大多数的别名只是为了使命令更简短，更容易打出。但是你如果不只要别名指向的命令名就很难读懂。

powershell内置的别名权衡了简洁性和清晰性。

例子：

002.创建新别名

使用Set-ALias可以给命令定义新的别名

但是已经内置的别名你是不能定义新别名覆盖的，不然会报错。

举例

PS> Set-Alias -Name gi -Value Get-Item
Set-Alias : Alias is not writeable because alias gi is read-only or constant and cannot be written to.
At line:1 char:10
+ Set-Alias  <<<< -Name gi -Value Get-Item

这样定义的别名只在当前会话有效，可以把别名写在自定义的$PROFILE文件中，这样每次打开终端都会执行一次设置别名的操作。实现自定义别名功能

04.获取详细帮助信息

001.获取关于cmd-let的帮助

Get-Helpcmdlet命令，可以获得关于cmdlet的信息

有以下两种方式获得帮助

比如:

Get-Help Get-ChildItem

或者:

Get-ChildItem -?

你也可以获得帮助的帮助,加上-Detailed（显示详细参数） -Full（显示所有信息） 选项可以获得更详细的信息。也可以只获得使用例子

-parameter选项查询制定参数

Get-Help Get-Help -Full

NAME
    Get-Help

SYNOPSIS
    Displays information about PowerShell commands and concepts.


SYNTAX
    Get-Help [[-Name] <String>] [-Category {Alias | Cmdlet | Provider | General | FAQ | Glossary | HelpFile | ScriptCo
    mmand | Function | Filter | ExternalScript | All | DefaultHelp | Workflow | DscResource | Class | Configuration}]
    [-Component <String[]>] -Detailed [-Functionality <String[]>] [-Path <String>] [-Role <String[]>] [<CommonParamete
    rs>]

    Get-Help [[-Name] <String>] [-Category {Alias | Cmdlet | Provider | General | FAQ | Glossary | HelpFile | ScriptCo
    mmand | Function | Filter | ExternalScript | All | DefaultHelp | Workflow | DscResource | Class | Configuration}]
    [-Component <String[]>] -Examples [-Functionality <String[]>] [-Path <String>] [-Role <String[]>] [<CommonParamete
    rs>]

    Get-Help [[-Name] <String>] [-Category {Alias | Cmdlet | Provider | General | FAQ | Glossary | HelpFile | ScriptCo
    mmand | Function | Filter | ExternalScript | All | DefaultHelp | Workflow | DscResource | Class | Configuration}]
    [-Component <String[]>] [-Full] [-Functionality <String[]>] [-Path <String>] [-Role <String[]>] [<CommonParameters
    >]

    Get-Help [[-Name] <String>] [-Category {Alias | Cmdlet | Provider | General | FAQ | Glossary | HelpFile | ScriptCo
    mmand | Function | Filter | ExternalScript | All | DefaultHelp | Workflow | DscResource | Class | Configuration}]
    [-Component <String[]>] [-Functionality <String[]>] -Online [-Path <String>] [-Role <String[]>] [<CommonParameters
    >]

    Get-Help [[-Name] <String>] [-Category {Alias | Cmdlet | Provider | General | FAQ | Glossary | HelpFile | ScriptCo
    mmand | Function | Filter | ExternalScript | All | DefaultHelp | Workflow | DscResource | Class | Configuration}]
    [-Component <String[]>] [-Functionality <String[]>] -Parameter <String> [-Path <String>] [-Role <String[]>] [<Comm
    onParameters>]

    Get-Help [[-Name] <String>] [-Category {Alias | Cmdlet | Provider | General | FAQ | Glossary | HelpFile | ScriptCo
    mmand | Function | Filter | ExternalScript | All | DefaultHelp | Workflow | DscResource | Class | Configuration}]
    [-Component <String[]>] [-Functionality <String[]>] [-Path <String>] [-Role <String[]>] -ShowWindow [<CommonParame
    ters>]


DESCRIPTION
    The `Get-Help` cmdlet displays information about PowerShell concepts and commands, including cmdlets, functions, C
    ommon Information Model (CIM) commands, workflows, providers, aliases, and scripts.

    To get help for a PowerShell cmdlet, type `Get-Help` followed by the cmdlet name, such as: `Get-Help Get-Process`.

    Conceptual help articles in PowerShell begin with about_ , such as about_Comparison_Operators . To see all about_
    articles, type `Get-Help about_*`. To see a particular article, type `Get-Help about_<article-name>`, such as `Get
    -Help about_Comparison_Operators`.

    To get help for a PowerShell provider, type `Get-Help` followed by the provider name. For example, to get help for
     the Certificate provider, type `Get-Help Certificate`.

    You can also type `help` or `man`, which displays one screen of text at a time. Or, `<cmdlet-name> -?`, that is id
    entical to `Get-Help`, but only works for cmdlets.

    `Get-Help` gets the help content that it displays from help files on your computer. Without the help files, `Get-H
    elp` displays only basic information about cmdlets. Some PowerShell modules include help files. Beginning in Power
    Shell 3.0, the modules that come with the Windows operating system don't include help files. To download or update
     the help files for a module in PowerShell 3.0, use the `Update-Help` cmdlet.

    You can also view the PowerShell help documents online in the Microsoft Docs. To get the online version of a help
    file, use the Online parameter, such as: `Get-Help Get-Process -Online`. To read all the PowerShell documentation,
     see the Microsoft Docs PowerShell Documentation (/powershell).

    If you type `Get-Help` followed by the exact name of a help article, or by a word unique to a help article, `Get-H
    elp` displays the article's content. If you enter a word or word pattern that appears in several help article titl
    es, `Get-Help` displays a list of the matching titles. If you enter a word that doesn't appear in any help article
     titles, `Get-Help` displays a list of articles that include that word in their contents.

    `Get-Help` can get help articles for all supported languages and locales. `Get-Help` first looks for help files in
     the locale set for Windows, then in the parent locale, such as pt for pt-BR , and then in a fallback locale. Begi
    nning in PowerShell 3.0, if `Get-Help` doesn't find help in the fallback locale, it looks for help articles in Eng
    lish, en-US , before it returns an error message or displaying autogenerated help.

    For information about the symbols that `Get-Help` displays in the command syntax diagram, see about_Command_Syntax
     (./About/about_Command_Syntax.md). For information about parameter attributes, such as Required and Position , se
    e about_Parameters (./About/about_Parameters.md).

    >[!NOTE] > In PowerShell 3.0 and PowerShell 4.0, `Get-Help` can't find About articles in modules unless > the modu
    le is imported into the current session. This is a known issue. To get About articles > in a module, import the mo
    dule, either by using the `Import-Module` cmdlet or by running a cmdlet > that's included in the module.


PARAMETERS
    -Category <String[]>
        Displays help only for items in the specified category and their aliases. Conceptual articles are in the HelpF
        ile category.

        The acceptable values for this parameter are as follows:

        - Alias

        - Cmdlet

        - Provider

        - General

        - FAQ

        - Glossary

        - HelpFile

        - ScriptCommand

        - Function

        - Filter

        - ExternalScript

        - All

        - DefaultHelp

        - Workflow

        - DscResource

        - Class

        - Configuration

        Required?                    false
        Position?                    named
        Default value                None
        Accept pipeline input?       False
        Accept wildcard characters?  false

    -Component <String[]>
        Displays commands with the specified component value, such as Exchange . Enter a component name. Wildcard char
        acters are permitted. This parameter has no effect on displays of conceptual ( About_ ) help.

        Required?                    false
        Position?                    named
        Default value                None
        Accept pipeline input?       False
        Accept wildcard characters?  true

    -Detailed [<SwitchParameter>]
        Adds parameter descriptions and examples to the basic help display. This parameter is effective only when the
        help files are installed on the computer. It has no effect on displays of conceptual ( About_ ) help.

        Required?                    true
        Position?                    named
        Default value                False
        Accept pipeline input?       False
        Accept wildcard characters?  false

    -Examples [<SwitchParameter>]
        Displays only the name, synopsis, and examples. To display only the examples, type `(Get-Help <cmdlet-name>).E
        xamples`.

        This parameter is effective only when the help files are installed on the computer. It has no effect on displa
        ys of conceptual ( About_ ) help.

        Required?                    true
        Position?                    named
        Default value                False
        Accept pipeline input?       False
        Accept wildcard characters?  false

    -Full [<SwitchParameter>]
        Displays the entire help article for a cmdlet. Full includes parameter descriptions and attributes, examples,
        input and output object types, and additional notes.

        This parameter is effective only when the help files are installed on the computer. It has no effect on displa
        ys of conceptual ( About_ ) help.

        Required?                    false
        Position?                    named
        Default value                False
        Accept pipeline input?       False
        Accept wildcard characters?  false

    -Functionality <String[]>
        Displays help for items with the specified functionality. Enter the functionality. Wildcard characters are per
        mitted. This parameter has no effect on displays of conceptual ( About_ ) help.

        Required?                    false
        Position?                    named
        Default value                None
        Accept pipeline input?       False
        Accept wildcard characters?  true

    -Name <String>
        Gets help about the specified command or concept. Enter the name of a cmdlet, function, provider, script, or w
        orkflow, such as `Get-Member`, a conceptual article name, such as `about_Objects`, or an alias, such as `ls`.
        Wildcard characters are permitted in cmdlet and provider names, but you can't use wildcard characters to find
        the names of function help and script help articles.

        To get help for a script that isn't located in a path that's listed in the `$env:Path` environment variable, t
        ype the script's path and file name.

        If you enter the exact name of a help article, `Get-Help` displays the article contents.

        If you enter a word or word pattern that appears in several help article titles, `Get-Help` displays a list of
         the matching titles.

        If you enter a word that doesn't match any help article titles, `Get-Help` displays a list of articles that in
        clude that word in their contents.

        The names of conceptual articles, such as `about_Objects`, must be entered in English, even in non-English ver
        sions of PowerShell.

        Required?                    false
        Position?                    0
        Default value                None
        Accept pipeline input?       True (ByPropertyName)
        Accept wildcard characters?  true

    -Online [<SwitchParameter>]
        Displays the online version of a help article in the default browser. This parameter is valid only for cmdlet,
         function, workflow, and script help articles. You can't use the Online parameter with `Get-Help` in a remote
        session.

        For information about supporting this feature in help articles that you write, see about_Comment_Based_Help (.
        /About/about_Comment_Based_Help.md), and Supporting Online Help (/powershell/scripting/developer/module/suppor
        ting-online-help), and Writing Help for PowerShell Cmdlets (/powershell/scripting/developer/help/writing-help-
        for-windows-powershell-cmdlets).

        Required?                    true
        Position?                    named
        Default value                False
        Accept pipeline input?       False
        Accept wildcard characters?  false

    -Parameter <String>
        Displays only the detailed descriptions of the specified parameters. Wildcards are permitted. This parameter h
        as no effect on displays of conceptual ( About_ ) help.

        Required?                    true
        Position?                    named
        Default value                None
        Accept pipeline input?       False
        Accept wildcard characters?  true

    -Path <String>
        Gets help that explains how the cmdlet works in the specified provider path. Enter a PowerShell provider path.

        This parameter gets a customized version of a cmdlet help article that explains how the cmdlet works in the sp
        ecified PowerShell provider path. This parameter is effective only for help about a provider cmdlet and only w
        hen the provider includes a custom version of the provider cmdlet help article in its help file. To use this p
        arameter, install the help file for the module that includes the provider.

        To see the custom cmdlet help for a provider path, go to the provider path location and enter a `Get-Help` com
        mand or, from any path location, use the Path parameter of `Get-Help` to specify the provider path. You can al
        so find custom cmdlet help online in the provider help section of the help articles.

        For more information about PowerShell providers, see about_Providers (./About/about_Providers.md).

        Required?                    false
        Position?                    named
        Default value                None
        Accept pipeline input?       False
        Accept wildcard characters?  true

    -Role <String[]>
        Displays help customized for the specified user role. Enter a role. Wildcard characters are permitted.

        Enter the role that the user plays in an organization. Some cmdlets display different text in their help files
         based on the value of this parameter. This parameter has no effect on help for the core cmdlets.

        Required?                    false
        Position?                    named
        Default value                None
        Accept pipeline input?       False
        Accept wildcard characters?  true

    -ShowWindow [<SwitchParameter>]
        Displays the help topic in a window for easier reading. The window includes a Find search feature and a Settin
        gs box that lets you set options for the display, including options to display only selected sections of a hel
        p topic.

        The ShowWindow parameter supports help topics for commands (cmdlets, functions, CIM commands, scripts) and con
        ceptual About articles. It does not support provider help.

        This parameter was reintroduced in PowerShell 7.0.

        Required?                    true
        Position?                    named
        Default value                False
        Accept pipeline input?       False
        Accept wildcard characters?  false

    <CommonParameters>
        This cmdlet supports the common parameters: Verbose, Debug,
        ErrorAction, ErrorVariable, WarningAction, WarningVariable,
        OutBuffer, PipelineVariable, and OutVariable. For more information, see
        about_CommonParameters (https://go.microsoft.com/fwlink/?LinkID=113216).

INPUTS
    None
        You can't send objects down the pipeline to `Get-Help`.


OUTPUTS
    ExtendedCmdletHelpInfo
        If you run `Get-Help` on a command that doesn't have a help file, `Get-Help` returns an ExtendedCmdletHelpInfo
         object that represents autogenerated help.

    System.String
        If you get a conceptual help article, `Get-Help` returns it as a string.

    MamlCommandHelpInfo
        If you get a command that has a help file, `Get-Help` returns a MamlCommandHelpInfo object.


NOTES


        PowerShell 3.0 doesn't include help files. To download and install the help files that `Get-Help` reads, use t
        he `Update-Help` cmdlet. You can use the `Update-Help` cmdlet to download and install help files for the core
        commands that come with PowerShell and for any modules that you install. You can also use it to update the hel
        p files so that the help on your computer is never outdated.

        You can also read the help articles about the commands that come with PowerShell online starting at Getting St
        arted with Windows PowerShell (/powershell/scripting/getting-started/getting-started-with-windows-powershell).

        `Get-Help` displays help in the locale set for the Windows operating system or in the fallback language for th
        at locale. If you don't have help files for the primary or fallback locale, `Get-Help` behaves as if there are
         no help files on the computer. To get help for a different locale, use Region and Language in Control Panel t
        o change the settings. On Windows 10, Settings , Time & Language .

        The full view of help includes a table of information about the parameters. The table includes the following f
        ields:

        - Required . Indicates whether the parameter is required (true) or optional (false).

        - Position . Indicates whether the parameter is named or positional (numeric). Positional   parameters must ap
        pear in a specified place in the command.

        - Named indicates that the parameter name is required, but that the parameter can appear   anywhere in the com
        mand.

        - Numeric indicates that the parameter name is optional, but when the name is omitted, the   parameter must be
         in the place specified by the number. For example, `2` indicates that when the   parameter name is omitted, t
        he parameter must be the second or only unnamed parameter in the   command. When the parameter name is used, t
        he parameter can appear anywhere in the command.

        - Default value . The parameter value or default behavior that PowerShell uses if you don't   include the para
        meter in the command.

        - Accepts pipeline input. Indicates whether you can (true) or can't (false) send objects to the   parameter th
        rough a pipeline. By Property Name means that the pipelined object must have a   property that has the same na
        me as the parameter name.

        - Accepts wildcard characters . Indicates whether the value of a parameter can include wildcard   characters,
        such as an asterisk (`*`) or question mark (`?`).

    --- Example 1: Display basic help information about a cmdlet ---

    Get-Help Format-Table
    Get-Help -Name Format-Table
    Format-Table -?

    `Get-Help <cmdlet-name>` is the simplest and default syntax of `Get-Help` cmdlet. You can omit the Name parameter.

    The syntax `<cmdlet-name> -?` works only for cmdlets.
    --- Example 2: Display basic information one page at a time ---

    help Format-Table
    man Format-Table
    Get-Help Format-Table | Out-Host -Paging

    `help` is a function that runs `Get-Help` cmdlet internally and displays the result one page at a time.

    `man` is an alias for the `help` function.

    `Get-Help Format-Table` sends the object down the pipeline. `Out-Host -Paging` receives the output from the pipeli
    ne and displays it one page at a time. For more information, see Out-Host (Out-Host.md).
    ------- Example 3: Display more information for a cmdlet -------

    Get-Help Format-Table -Detailed
    Get-Help Format-Table -Full

    The Detailed parameter displays the help article's detailed view that includes parameter descriptions and examples
    .

    The Full parameter displays the help article's full view that includes parameter descriptions, examples, input and
     output object types, and additional notes.

    The Detailed and Full parameters are effective only for the commands that have help files installed on the compute
    r. The parameters aren't effective for the conceptual ( about_ ) help articles.
    Example 4: Display selected parts of a cmdlet by using parameters

    Get-Help Format-Table -Examples
    Get-Help Format-Table -Parameter *
    Get-Help Format-Table -Parameter GroupBy

    The Examples parameter displays the help file's NAME and SYNOPSIS sections, and all the Examples. You can't specif
    y an Example number because the Examples parameter is a switch parameter.

    The Parameter parameter displays only the descriptions of the specified parameters. If you specify only the asteri
    sk (`*`) wildcard character, it displays the descriptions of all parameters. When Parameter specifies a parameter
    name such as GroupBy , information about that parameter is shown.

    These parameters aren't effective for the conceptual ( about_ ) help articles.
    ---------- Example 5: Display online version of help ----------

    Get-Help Format-Table -Online


    -------- Example 6: Display help about the help system --------

    Get-Help


    ---------- Example 7: Display available help articles ----------

    Get-Help *


    ------- Example 8: Display a list of conceptual articles -------

    Get-Help about_*


    --------- Example 9: Search for a word in cmdlet help ---------

    Get-Help Add-Member -Full | Out-String -Stream | Select-String -Pattern Clixml

    the Export-Clixml cmdlet to save the instance of the object, including the additional members...
    can use the Import-Clixml cmdlet to re-create the instance of the object from the information...
    Export-Clixml
    Import-Clixml

    `Get-Help` uses the Full parameter to get help information for `Add-Member`. The MamlCommandHelpInfo object is sen
    t down the pipeline. `Out-String` uses the Stream parameter to convert the object into a string. `Select-String` u
    ses the Pattern parameter to search the string for Clixml .
    -- Example 10: Display a list of articles that include a word --

    Get-Help -Name remoting

    Name                              Category  Module                    Synopsis
    ----                              --------  ------                    --------
    Install-PowerShellRemoting.ps1    External                            Install-PowerShellRemoting.ps1
    Disable-PSRemoting                Cmdlet    Microsoft.PowerShell.Core Prevents remote users...
    Enable-PSRemoting                 Cmdlet    Microsoft.PowerShell.Core Configures the computer...


    ---------- Example 11: Display provider-specific help ----------

    Get-Help Get-Item -Path SQLSERVER:\DataCollection

    NAME

        Get-Item

    SYNOPSIS

        Gets a collection of Server objects for the local computer and any computers

        to which you have made a SQL Server PowerShell connection.
        ...

    Set-Location SQLSERVER:\DataCollection
    SQLSERVER:\DataCollection> Get-Help Get-Item

    NAME

        Get-Item

    SYNOPSIS

        Gets a collection of Server objects for the local computer and any computers

        to which you have made a SQL Server PowerShell connection.
        ...


    ------------ Example 12: Display help for a script ------------

    Get-Help -Name C:\PS-Test\MyScript.ps1



RELATED LINKS
    Online Version: https://docs.microsoft.com/powershell/module/microsoft.powershell.core/get-help?view=powershell-7&
    WT.mc_id=ps-gethelp
    about_Command_Syntax
    about_Comment_Based_Help
    Get-Command
    Supporting Updatable Help
    Update-Help
    Writing Comment-Based Help Topics
    Writing Help for PowerShell Cmdlets

002.获取概念上的帮助

Get-Help命令也内置了一些关于语法概念之类的文章，这些帮助文档会以about_开头

执行下面的命令

Get-Help about_*

我们发现有很多使用的帮助文档。我之前买书就买亏了，这么详细的文档，学起来就不需要别的书了

Name                              Category  Module                    Synopsis
----                              --------  ------                    --------
about_PSReadLine                  HelpFile
about_Aliases                     HelpFile
about_Alias_Provider              HelpFile
about_Arithmetic_Operators        HelpFile
about_Arrays                      HelpFile
about_Assignment_Operators        HelpFile
about_Automatic_Variables         HelpFile
about_Break                       HelpFile
about_Certificate_Provider        HelpFile
about_CimSession                  HelpFile
about_Classes                     HelpFile
about_Command_Precedence          HelpFile
about_Command_Syntax              HelpFile
about_Comment_Based_Help          HelpFile
about_CommonParameters            HelpFile
about_Comparison_Operators        HelpFile
about_Continue                    HelpFile
about_Core_Commands               HelpFile
about_Data_Sections               HelpFile
about_Debuggers                   HelpFile
about_Do                          HelpFile
about_Enum                        HelpFile
about_Environment_Provider        HelpFile
about_Environment_Variables       HelpFile
about_Execution_Policies          HelpFile
about_Experimental_Features       HelpFile
about_FileSystem_Provider         HelpFile
about_For                         HelpFile
about_Foreach                     HelpFile
about_Format.ps1xml               HelpFile
about_Functions                   HelpFile
about_Functions_Advanced          HelpFile
about_Functions_Advanced_Methods  HelpFile
about_Functions_Advanced_Paramet… HelpFile
about_Functions_CmdletBindingAtt… HelpFile
about_Functions_OutputTypeAttrib… HelpFile
about_Function_Provider           HelpFile
about_Group_Policy_Settings       HelpFile
about_Hash_Tables                 HelpFile
about_Hidden                      HelpFile
about_History                     HelpFile
about_If                          HelpFile
about_Jobs                        HelpFile
about_Job_Details                 HelpFile
about_Join                        HelpFile
about_Language_Keywords           HelpFile
about_Language_Modes              HelpFile
about_Line_Editing                HelpFile
about_Locations                   HelpFile
about_Logging_Non-Windows         HelpFile
about_Logging_Windows             HelpFile
about_Logical_Operators           HelpFile
about_Methods                     HelpFile
about_Modules                     HelpFile
about_Numeric_Literals            HelpFile
about_Objects                     HelpFile
about_Object_Creation             HelpFile
about_Operators                   HelpFile
about_Operator_Precedence         HelpFile
about_PackageManagement           HelpFile
about_Parameters                  HelpFile
about_Parameters_Default_Values   HelpFile
about_Parameter_Sets              HelpFile
about_Parsing                     HelpFile
about_Path_Syntax                 HelpFile
about_Pipelines                   HelpFile
about_Pipeline_Chain_Operators    HelpFile
about_PowerShell_Config           HelpFile
about_PowerShell_Editions         HelpFile
about_Preference_Variables        HelpFile
about_Profiles                    HelpFile
about_Prompts                     HelpFile
about_Properties                  HelpFile
about_Providers                   HelpFile
about_PSConsoleHostReadLine       HelpFile
about_PSSessions                  HelpFile
about_PSSession_Details           HelpFile
about_Pwsh                        HelpFile
about_Quoting_Rules               HelpFile
about_Redirection                 HelpFile
about_Ref                         HelpFile
about_Registry_Provider           HelpFile
about_Regular_Expressions         HelpFile
about_Remote                      HelpFile
about_Remote_Disconnected_Sessio… HelpFile
about_Remote_FAQ                  HelpFile
about_Remote_Jobs                 HelpFile
about_Remote_Output               HelpFile
about_Remote_Requirements         HelpFile
about_Remote_Troubleshooting      HelpFile
about_Remote_Variables            HelpFile
about_Requires                    HelpFile
about_Reserved_Words              HelpFile
about_Return                      HelpFile
about_Run_With_PowerShell         HelpFile
about_Scopes                      HelpFile
about_Scripts                     HelpFile
about_Script_Blocks               HelpFile
about_Script_Internationalization HelpFile
about_Session_Configurations      HelpFile
about_Session_Configuration_Files HelpFile
about_Signing                     HelpFile
about_Simplified_Syntax           HelpFile
about_Special_Characters          HelpFile
about_Splatting                   HelpFile
about_Split                       HelpFile
about_Switch                      HelpFile
about_Telemetry                   HelpFile
about_Thread_Jobs                 HelpFile
about_Throw                       HelpFile
about_Trap                        HelpFile
about_Try_Catch_Finally           HelpFile
about_Types.ps1xml                HelpFile
about_Type_Operators              HelpFile
about_Updatable_Help              HelpFile
about_Update_Notifications        HelpFile
about_Using                       HelpFile
about_Variables                   HelpFile
about_Variable_Provider           HelpFile
about_While                       HelpFile
about_Wildcards                   HelpFile
about_Windows_PowerShell_Compati… HelpFile
about_WSMan_Provider              HelpFile
about_BeforeEach_AfterEach        HelpFile                            performed at the beginning and end of every It …
about_Mocking                     HelpFile                            Pester provides a set of Mocking functions maki…
about_Pester                      HelpFile                            Pester is a BDD based test runner for PowerShel…
about_should                      HelpFile                            Provides assertion convenience methods for comp…
about_TestDrive                   HelpFile                            A PSDrive for file activity limited to the scop…
about_Scheduled_Jobs              HelpFile                            Describes scheduled jobs and explains how to us…
about_Scheduled_Jobs_Advanced     HelpFile                            Explains advanced scheduled job topics, includi…
about_Scheduled_Jobs_Basics       HelpFile                            Explains how to create and manage scheduled job…
about_Scheduled_Jobs_Troubleshoo… HelpFile                            Explains how to resolve problems with scheduled…
about_ActivityCommonParameters    HelpFile                            Describes the parameters that Windows PowerShell
about_Checkpoint-Workflow         HelpFile                            Describes the Checkpoint-Workflow activity, whi…
about_ForEach-Parallel            HelpFile                            Describes the ForEach -Parallel language constr…
about_InlineScript                HelpFile                            Describes the InlineScript activity, which runs…
about_Parallel                    HelpFile                            Describes the Parallel keyword, which runs the
about_Sequence                    HelpFile                            Describes the Sequence keyword, which runs sele…
about_Suspend-Workflow            HelpFile                            Describes the Suspend-Workflow activity, which …
about_WorkflowCommonParameters    HelpFile                            This topic describes the parameters that are va…
about_Workflows                   HelpFile                            Provides a brief introduction to the Windows

003.获取provider相关信息

provider是基于.net的程序帮助你管理powrershell中存储的信息

你可以像访问磁盘驱动器访问目录访问文件一样访问他们，可以使用cd ls 命令查看

有一些内置的provider

Built-in providers

PowerShell includes a set of built-in providers that you can use to access
the different types of data stores.

  Provider      Drive          Data store
  ------------- -------------- --------------------------------------------
  Alias         Alias:         PowerShell aliases
  Certificate   Cert:          x509 certificates for digital signatures
  Environment   Env:           Windows environment variables
  FileSystem    (*)            File system drives, directories, and files
  Function      Function:      PowerShell functions
  Registry      HKLM:, HKCU:   Windows registry
  Variable      Variable:      PowerShell variables
  WSMan         WSMan:         WS-Management configuration information

获取注册表相关帮助

Get-Help registry

004.获取脚本和函数的帮助

有些脚本或函数也有帮助文档，可以用Get-Help显示

005.获取网上的帮助文档

最好的帮助文档是网上的，因为是实时更新的。使用Get-Help命令的时候记得加上online选项。

05.获取命令相关信息

Get-Command命令可以显示当前存在的命令。

执行这个命令后会显示类似下面的输出

CommandType     Name                    Version    Source
-----------     ----                    -------    ------
Cmdlet          Add-Computer            3.1.0.0    Microsoft.PowerShell.Management
Cmdlet          Add-Content             3.1.0.0    Microsoft.PowerShell.Management
Cmdlet          Add-History             3.0.0.0    Microsoft.PowerShell.Core
Cmdlet          Add-JobTrigger          1.1.0.0    PSScheduledJob
Cmdlet          Add-LocalGroupMember    1.0.0.0    Microsoft.PowerShell.LocalAccounts
Cmdlet          Add-Member              3.1.0.0    Microsoft.PowerShell.Utility
Cmdlet          Add-PSSnapin            3.0.0.0    Microsoft.PowerShell.Core
Cmdlet          Add-Type                3.1.0.0    Microsoft.PowerShell.Utility
...

有一个syntax选项可以帮助显示每个cmdlet命令的语法

比如执行西面这行命令。

Get-Command Get-Help -Syntax

命令分为以下几种类型：

• Aliases
• Functions
• Scripts

我们可以用命令类型来获取命令

Get-Command -CommandType Function

06.使用变量来存储对象

​ powershell中的变量名由英文字母，数字和下划线组成。当在powershell

中使用变量，需要在变量名前加上$符号

创建一个变量很简单,此时变量没有值，所以不会有输出

$loc

下面是创建并赋值。

$loc = Get-Location

然后就有输出了

PS> $loc

Path
----
C:\temp

可以使用Get-Member命令获取一个变量的相关信息

PS> $loc | Get-Member -MemberType Property

   TypeName: System.Management.Automation.PathInfo

Name         MemberType Definition
----         ---------- ----------
Drive        Property   System.Management.Automation.PSDriveInfo Drive {get;}
Path         Property   System.String Path {get;}
Provider     Property   System.Management.Automation.ProviderInfo Provider {...
ProviderPath Property   System.String ProviderPath {get;}

001.变量操作

powershell提供了一些变量操作的命令，输入下面这条命令来查看

Get-Command -Noun Variable | Format-Table -Property Name,Definition -AutoSize -Wrap

Name            Definition
----            ----------
Clear-Variable
                Clear-Variable [-Name] <string[]> [-Include <string[]>] [-Exclude <string[]>] [-Force] [-PassThru] [-S
                cope <string>] [-WhatIf] [-Confirm] [<CommonParameters>]

Get-Variable
                Get-Variable [[-Name] <string[]>] [-ValueOnly] [-Include <string[]>] [-Exclude <string[]>] [-Scope <st
                ring>] [<CommonParameters>]

New-Variable
                New-Variable [-Name] <string> [[-Value] <Object>] [-Description <string>] [-Option <ScopedItemOptions>
                ] [-Visibility <SessionStateEntryVisibility>] [-Force] [-PassThru] [-Scope <string>] [-WhatIf] [-Confi
                rm] [<CommonParameters>]

Remove-Variable
                Remove-Variable [-Name] <string[]> [-Include <string[]>] [-Exclude <string[]>] [-Force] [-Scope <strin
                g>] [-WhatIf] [-Confirm] [<CommonParameters>]

Set-Variable
                Set-Variable [-Name] <string[]> [[-Value] <Object>] [-Include <string[]>] [-Exclude <string[]>] [-Desc
                ription <string>] [-Option <ScopedItemOptions>] [-Force] [-Visibility <SessionStateEntryVisibility>] [
                -PassThru] [-Scope <string>] [-WhatIf] [-Confirm] [<CommonParameters>]

powershell 也存在系统定义的变量（不能被这几个变量命令控制），可以使用 Remove-Variable 来移除。

输入下面的命令来移除所有变量

Remove-Variable -Name * -Force -ErrorAction SilentlyContinue

此时执行Get-Variable命令看到的都是系统变量

powershell也创建了一个变量驱动器，可以使用下面的命令显示所有powershell变量

Get-ChildItem variable:

002.使用环境变量

powershell和所有其他windows进程共用一套环境变量，包括cmd。

可以使用env驱动器进行查看

执行下面的命令查看所有的环境变量

Get-ChildItem env:

上面提到的*-Variable命令并不能用于处理环境变量

环境变量只能够通过env驱动器访问，比如访问%SystemRoot%变量

PS> $env:SystemRoot
C:\WINDOWS

你也可以使用powershell创建和修改环境变量

比如

$env:LIB_PATH='/usr/local/lib'

07.理解powershell管道

001.powershell管道

管道可能是命令行接口中中最有价值的概念之一。使用得当，可以减少复杂的命令，看清命令工作流程。每个管道中的命令行都把他的输出传送给下一个命令。逐个项目处理，管道不需要处理超过一个项目。

举个例子，使用Out-Host命令分页输出其他命令的输出

Get-ChildItem -Path C:\WINDOWS\System32 | Out-Host -Paging

会输出类似下面的内容:

    Directory: C:\WINDOWS\system32

Mode                LastWriteTime         Length Name
----                -------------         ------ ----
d-----        4/12/2018   2:15 AM                0409
d-----        5/13/2018  11:31 PM                1033
d-----        4/11/2018   4:38 PM                AdvancedInstallers
d-----        5/13/2018  11:13 PM                af-ZA
d-----        5/13/2018  11:13 PM                am-et
d-----        4/11/2018   4:38 PM                AppLocker
d-----        5/13/2018  11:31 PM                appmgmt
d-----        7/11/2018   2:05 AM                appraiser
d---s-        4/12/2018   2:20 AM                AppV
d-----        5/13/2018  11:10 PM                ar-SA
d-----        5/13/2018  11:13 PM                as-IN
d-----        8/14/2018   9:03 PM                az-Latn-AZ
d-----        5/13/2018  11:13 PM                be-BY
d-----        5/13/2018  11:10 PM                BestPractices
d-----        5/13/2018  11:10 PM                bg-BG
d-----        5/13/2018  11:13 PM                bn-BD
d-----        5/13/2018  11:13 PM                bn-IN
d-----        8/14/2018   9:03 PM                Boot
d-----        8/14/2018   9:03 PM                bs-Latn-BA
d-----        4/11/2018   4:38 PM                Bthprops
d-----        4/12/2018   2:19 AM                ca-ES
d-----        8/14/2018   9:03 PM                ca-ES-valencia
d-----        5/13/2018  10:46 PM                CatRoot
d-----        8/23/2018   5:07 PM                catroot2
<SPACE> next page; <CR> next line; Q quit
...

这样可以减少资源占用，因为，Out-Host命令只有当完整的一页准备好的时候才会输出，管道前面的命令会停止执行直到下一页加载完成。

你可以使用任务管理器，比较下面两个命令的资源占用，包括cpu和内存

• Get-ChildItem C:\Windows -Recurse
• Get-ChildItem C:\Windows -Recurse | Out-Host -Paging

002.管道中的对象

当你在powershell中执行一个cmdlet，你会看到文本输出，因为需要用文本表示对象，以便在控制台窗口中显示出来。文本输出可能不会显示所有输出对象的属性。

举个例子，

PS> Get-Location
Path
----
C:\

当你使用Get-Location命令时，你只得到了一个信息的总结，而不是是对象的完整描述。

当你使用管道把结果传递给Get-Member命令式，你将会得到这个对象的信息。

Get-Location | Get-Member

   TypeName: System.Management.Automation.PathInfo

Name         MemberType Definition
----         ---------- ----------
Equals       Method     bool Equals(System.Object obj)
GetHashCode  Method     int GetHashCode()
GetType      Method     type GetType()
ToString     Method     string ToString()
Drive        Property   System.Management.Automation.PSDriveInfo Drive {get;}
Path         Property   string Path {get;}
Provider     Property   System.Management.Automation.ProviderInfo Provider {get;}
ProviderPath Property   string ProviderPath {get;}

08.可移植模块

windows下自带的powershell是基于 .NET Framework，另外有一套跨平台的powershell，叫做PowerShell Core是基于 .NET Core.编写的。

可移植模块指的是在这两种powershell中都能运行的模块。

两套powershell的api高度兼容，但是也有一些api是有所不同的，编写可移植模块的时候要注意这些不同

下面的内容主要是用.net编写powershell模块的，因为暂时用不到，所以先跳过

001.移植一个已经存在的模块

002.创建一个新模块

003..NET标准库

09.powershell远程操作

暂时用不到，跳过。

10.powershell术语表