aman5898 / Learning-PowerShell

Difference Between Powershell and cmd

1. PowerShell uses cmdlets, which are self-contained programming objects that expose the underlying administration options inside of Windows.

2. PowerShell uses pipes to chain together cmdlets and share input/output data the same way as other shells, like bash in linux.

3. One of the (many) neat functions of PowerShell is the ability to create aliases for different cmdlets. Aliases allow a user to configure their own names for different cmdlets or scripts, which makes it more straightforward for a user to switch back and forth between different shells: ‘ls’ is a linux bash command that displays directory objects, like the ‘dir’ command. In PowerShell, both ‘ls’ and ‘dir’ are an alias for the cmdlet ‘Get-ChildItem.’

4. CMD is the older “shell” or “batch” language going back in some form (command.com) to the original DOS operating system.

5. PowerShell is the new and vastly improved shell and programming language first made available as an add-on and now included (and now enabled) in the Windows operating systems.

6. PowerShell passes and returns OBJECTS (structured data with methods, events, and properties) to other commands and returns these objects from most commands as well while CMD produces only text.

Resources to Help you

PowerShell.org

By default power shell will not run scripts

.ps1, .psm1, .ps1xml files

Execution Policy

Acess for Scripts to run

• Restricted
• Remote Signed
• AllSigned
• UnRestricted
• ByPass

The Least suggested is Remote Signed

Open Power Shell as Administrator

Set-ExecutionPolicy RemoteSigned
                or
Set-ExecutionPolicy unrestricted -Force

RemoteSigned says run any script made locally but not downloaded from internet unless its digitally Signed

This Command will open up the current folder in explorer or with the default program

invoke-item .

This will checkout the unblock checkbox on the file property downloaded via internet

unblock-file filnameWithAddress

• Power Shell Executes in a given scope
• Things defined in scope ends with it
• Scripts runs in their own scope

Scopes

• Global
  • Powershell opens in this scope
• Script
  • Scrips runs in their own internal Scope.
• Local
  • The current scope. The local scope can be the global scope or any other scope.
• Private
• Numbered Scops

If follows Lexical Scoping

We can create or write in only current scope

We can use -Scope parameter in case a variable needs to declare in a particular scope.

Everything in PowerShell ISE runs in Global Scope

To learn more about scopes

help about-scopes

To get all the variables in the global scope, type:

Get-Variable -Scope global

We can create a powershell profile to meet your needs as per Ide or different conditions

It has

• Hard Coded File Paths
• You will have to create them

Some of the PowerShell Profile e.g,

Even when I am executing my script in VScode or somewhere else It has some Powershell Profile

A basic script file is a text file with .ps1 file extension

• Use # to indicate comments

Another Example

It will create and Html file with the results and Also will add css to it

We can also pass parameters to the script

use Help Script Name and it will tell you the parameters the script is expecting

Using IF Else

Enumeration

Two ways to do it

• ForEach-Object
• For Each

1. ForEach-Object

2. ForEach

In the ForEachObject way we can pipe the result to the end while we can't do the same in forEach 2nd Method

Array

Array Operations

HashTables

Also, we can Update HashTable

We also have one ordered HashTable in PS

Splatting in HashTable

Here we reference the variable using @

Objects in Pipeline

• Select
• New
• [pscustomobject]

We also have try/catch in PS

With String Data Type we can have all the methods that we use in Java/C++

Same Goes for Date Data Type

Piping the Date variable with get-member and then with more can be done with other data types too

To see everything which is in date referenced variable we can have

$now = get-Date
$now | select *
$now.dayOfWeek

PS has a class call Math class or more directly its in dotnet

To find all things in Math Class

To invoke methods

We also have Powershell script that orchestrates or runs other powershell commands, functions and scripts

Things to learn further in PowerShell

Other resource

• PowerShell.org
• Http://bit.ly/PSUserGroups