set variable name by typing $name="mark"
typing the variable name, and then pressing enter will print the variable name
integers 
string ""
$name.GetType()
variables can be used within variables.
$name="mark"
$sentence = "Hi $name welcome to PowerShell" will output Hi mark welcome to PowerShell
$sentence = 'Hi $name welcome to PowerShell' will output Hi $name welcome to PowerShell
The GetType Method

DataTypes
[int]$test1 = 100 declaring [int] will force the variable to store only integer type data
[string]$name = "Mark" will force the variable to store only string type data.
[datetime]$date = 12/12/2018

Read-Host takes input from the user
[int]$sentence = Read-Host "what is your age" this will prompt the user for input, and will only accept integers

everything in PowerShell is an object.
every object has certain methods associated with it.
$text | Get-member - to view methods of an object.
$foo.equals(12) - will return true if the value of $foo is 12 else will return false.
$text.contains("hey") - will return true if the string has the keyword 'hey' in it
$text.replace("The","A") - will replace The with A

PowerShell Commands, many start with:
Add-
Clear-
Connect-
ConvertFrom-
ConvertTo-
Copy-
Disable-
Enable-
Export-
Get-
Import-
Invoke-
Move-
New-
Remove-
Rename-
Repair-
Reset-
Set-
Show-
Update- 
This list is by no
32x10x4+32X5
total available commands in command list. ~1500


$foo.Contains("where")
false

$age = 25
$age | get-member

$age.Equals(12)
false

$text = "the quick brown fox jumps over the lazy dog"
$text.replace("The", "A")

//is case sensitive