Shulou(Shulou.com)06/02 Report--

Let's start with four sentences:

First, if you want to filter objects, you can use Where-Object

Second, if you want to filter the properties of the object, you can use Select-Object

Third, if you want to customize the filtering effect, you can use ForEach-Object

Fourth, if you want to filter duplicate results, you can use Get-Unique

Then add to the understanding of-Filter in some command lines, Filter will appear in some commands, which also means filtering. I checked the document for a long time and did not have a clear explanation, but suddenly got an official explanation from the explanation of a command:

Query all the help for a command, as follows:

PS C:\ > help Get-WmiObject-full

NAME

Get-WmiObject

SYNOPSIS

Gets instances of WMI classes or information about the available classes.

SYNTAX

Get-WmiObject [- Class] [[- Property]] [- Amended] [- AsJob] [- Authentication {Default | None |

Connect | Call | Packet | PacketIntegrity | PacketPrivacy | Unchanged}] [- Authority] [- ComputerName

] [- Credential] [- DirectRead] [- EnableAllPrivileges] [- Filter] [- Impersonation

{Default | Anonymous | Identify | Impersonate | Delegate}] [- Locale] [- Namespace]

[- ThrottleLimit] []

There is a-filter parameter in this command, which is explained in detail as follows:

-Filter

Specifies a Where clause to use as a filter. Uses the syntax of the WMI Query Language (WQL).

Important: Do not include the Where keyword in the value of the parameter. For example, the following commands

Return only the logical disks that have a DeviceID of'cpura 'and services that have the name' WinRM' without

Using the Where keyword.

`Get-WmiObject Win32_LogicalDisk-filter "DeviceID = 'cblol'" `

`Get-WmiObject win32_service-filter "name='WinRM'" `

Required? False

Position? Named

Default value None

Accept pipeline input? False

Accept wildcard characters? False

My understanding of this explanation is that, first of all, not all commands support the-filter parameter. For supported commands, the syntax followed is WMI query language. If you want to check meaning too much, study it yourself.

Prepare the data source, in fact, I just want to see how many properties an object has, and then call it at once.

PS C:\ > Get-Service | Select-Object-First 1 | Get-Member-MemberType Properties

TypeName: System.ServiceProcess.ServiceController

Name MemberType Definition

-

Name AliasProperty Name = ServiceName

RequiredServices AliasProperty RequiredServices = ServicesDependedOn

CanPauseAndContinue Property bool CanPauseAndContinue {get;}

CanShutdown Property bool CanShutdown {get;}

CanStop Property bool CanStop {get;}

Container Property System.ComponentModel.IContainer Container {get;}

DependentServices Property System.ServiceProcess.ServiceController [] DependentServices {get;}

DisplayName Property string DisplayName {get;set;}

MachineName Property string MachineName {get;set;}

ServiceHandle Property System.Runtime.InteropServices.SafeHandle ServiceHandle {get;}

ServiceName Property string ServiceName {get;set;}

ServicesDependedOn Property System.ServiceProcess.ServiceController [] ServicesDependedOn {get;}

ServiceType Property System.ServiceProcess.ServiceType ServiceType {get;}

Site Property System.ComponentModel.ISite Site {get;set;}

StartType Property System.ServiceProcess.ServiceStartMode StartType {get;}

Status Property System.ServiceProcess.ServiceControllerStatus Status {get;}

First, if you want to filter objects, you can use Where-Object

PS C:\ > Get-Service | Where-Object {$_ .status-eq "Running"}

Status Name DisplayName

-

Running AdobeARMservice Adobe Acrobat Update Service

Running Appinfo Application Information

Running Apple Mobile De... Apple Mobile Device Service

Running AppMgmt Application Management

Running AudioEndpointBu... Windows Audio Endpoint Builder

Running Audiosrv Windows Audio

Running BDESVC BitLocker Drive Encryption Service

The understanding of this command is that where itself means a condition, and then an instruction block is followed to specify the specific condition. In other words, I want to see which services are running now. $_ represents the current object. There is no explanation for the point.

Second, if you want to filter the properties of the object, you can use Select-Object

When we find out what we want, we still have some ideas. in general, only part of the attributes of the object are displayed, so we have to see what to do with the attributes of the specified object. SO EASY

PS C:\ > Get-Service | Where-Object {$_ .status-eq "Running"} | Select-Object Name,MachineName,Site,Status

Name MachineName Site Status

AdobeARMservice. Running

Appinfo. Running

Apple Mobile Device Service. Running

AppMgmt. Running

AudioEndpointBuilder. Running

Audiosrv. Running

BDESVC. Running

To use a sentence that all Chinese can understand is to see which attribute to write which attribute.

Third, if you want to customize the filtering effect, you can use ForEach-Object

This has to be another example. At the same time, there is a playful placeholder that can be used. It looks noble and noble, but it is actually very EASY.

The above code:

PS C:\ > ls | ForEach-Object {"FileName: {0} FileSize {1:n2} KB"-f $_ .name, ($_ .length / 1kb)}

FileName:XMPCache FileSize0.00KB

FileName:baseline.xml FileSize30812.20KB

It looks disgusting, but in a simple sense, the LS command produces a lot of object sets and then processes them with FOREACH-OBJECT. The following code block is the condition for execution, {0} {1:n2}-f $_ .name, ($_ .length / 1kb)}

The understanding of this matter is that 0recovery1 stands for placeholder. It's simple. {1:n2} N2, it looks very tall, but in fact, N stands for numbers, 2, hehe, keep two decimal places. If these things are not explained, hehe, before I was very do not understand, read a lot of documents, in fact, SO EASY.

Fourth, if you want to filter duplicate results, you can use Get-Unique

This literal translation is to get the only value. For instance.

PS C:\ > ls | ForEach-Object {$_ .Extension} | Sort-Object | Get-Unique

.csv

.docx

.html

.log

.ps1

.txt

.xlsx

.xml

PS C:\ >

In the interpretation of this command, LS wants to get the current directory object, then look for the extension of the current file, throw it into a pipe to sort, and then throw it into a pipe to remove duplicates. Remember that everything you throw around is just operating on an object set.

The command and syntax of POWERSHELL are complicated, but as long as you understand the principle, you can SO EASY it. Nothing is difficult, as long as you are willing to climb.

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