Hi Guys, 
 Before start learning PowerShell first we need to clear or learn some basic logics and basic  steps of scripting, that’s why I decide to learn about wildcards first. So Lets Start 
 Question: what are wildcards?
 Answer: A wildcard character can be used to substitute for any other character or characters in a string.
 Question: Which wildcards are available in PowerShell and what are there meaning?
 Answer: The wildcards are available in PowerShell are * ? and []
    | Wildcard | Description | 
  | * | matches Zero or More characters | 
  | ? | match Exactly one character | 
  | [a-z] | matches a range of characters | 
  | [abc] | matches specified character | 
  
 Examples
 Wildcard * 
 Lets Run the following command: Dir * it shows all file and folders in current Directory 
   
 
 Let run another command: Dir *.* it will show all files in current directory. *.* means all file with any file extension
  
 
 Lets search for all .mp3 files in our current directory.: Dir *.mp3
  
 
 Now lets search for all file and folders which starts with B: Dir b* 
  
 
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 Wildcard ?
 Now let try our another wildcard character ? , in this example we are searching for a .txt file which names end with at and we forget what  is the name: dir ?at.txt   this command return all file which has at.txt at the end.
  
 
 Let See the another Example, in this example i am looking for a txt whose name is 3 character long. Dir ???.txt
       
 
 Now lets join our both wildcards and search for all .mp3 and .mp4 available in our current directory: dir *.mp?
  
 
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   Wildcard [] matches specify range of characters
 In [] wildcard we can specify a range of characters to match , for example if we specify [a-d] then it means all alphabets between A-D (A,B,C,D) or if we specified [1-8] then it means match all digits between 1-8 (1,2,3,4,5,6,7,8)
 Dir: [a-z]at.txt  this command check for all file start with a-z character and at.txt at the end
  
 
 In another example lets search for all folder starts whose name start from 1-6
 Dir [1-6]
  
 
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  Wildcard [] matches specify characters
 In this wildcard rather then provide a range we specify which characters we want to match. for example we want to match character start with b,c,d then we can specify it as [acd] then it matched only files or folders starts with A,C,D and ignore everything else.
 For example: dir [bcl]ook.txt , this command look for all files start with B,C,L and have ook.txt after it 
  
 
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 I hope this article helps you to understand Wildcards a little bit :)
 Thanks for reading it
 Regards
 Aman Dhally
  
 Note: Dir command is an alias of Get-Childtem in PowerShell