New Delhi PowerShell User Group.: Wildcards in PowerShell

Thursday, August 25, 2011

Wildcards in PowerShell

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