Variables in PowerShell All Versions

Examples

• 2

  Removing a variable
  2

  To remove a variable from memory, one can use the Remove-Item cmdlet. Note: The variable name does NOT include the $.

  Remove-Item Variable:\foo
  

  Variable has a provider to allow most *-item cmdlets to work much like file systems.

  Another method to remove variable is to use Remove-Variable cmdlet and its alias rv

  $var = "Some Variable" #Define variable 'var' containing the string 'Some Variable'
  $var #For test and show string 'Some Variable' on the console
  
  Remove-Variable -Name var
  $var 
  
  #also can use alias 'rv'
  rv var
  

  edited Aug 29 '16 at 7:13

  

  
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• 1

  Arrays
  1

  Array declaration in Powershell is almost the same as instantiating any other variable, i.e. you use a $name = syntax. The items in the array are declared by separating them by commas(,):

  $myArrayOfInts = 1,2,3,4
  $myArrayOfStrings = "1","2","3","4"
  

  Adding to an arry

  Adding to an array is as simple as using the + operator:

  $myArrayOfInts = $myArrayOfInts + 5
  //now contains 1,2,3,4 & 5!
  

  Combining arrays together

  Again this is as simple as using the + operator

  $myArrayOfInts = 1,2,3,4
  $myOtherArrayOfInts = 5,6,7
  $myArrayOfInts = $myArrayOfInts + $myOtherArrayOfInts
  //now 1,2,3,4,5,6,7
  

  created Dec 9 '16 at 10:21

  
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• 1

  Scope
  1

  The default scope for a variable is the enclosing container. If outside a script, or other container then the scope is Global. To specify a scope, it is prefixed to the variable name $scope:varname like so:

  $foo = "Global Scope"
  function myFunc {
      $foo = "Function (local) scope"
      Write-Host $global:foo
      Write-Host $local:foo
      Write-Host $foo
  }
  myFunc
  Write-Host $local:foo
  Write-Host $foo
  

  Output:

      Global Scope
      Function (local) scope
      Function (local) scope
      Global Scope
      Global Scope
  

  created Jul 25 '16 at 0:48

  
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• 1

  Simple variable
  1

  All variables in powershell begin with a US dollar sign ($). The simplest example of this is:

  $foo = "bar"
  

  This statement allocates a variable called foo with a string value of "bar".

  created Jul 25 '16 at 0:48

  
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• 0

  List Assignment of Multiple Variables
  0

  Powershell allows multiple assignment of variables and treats almost everything like an array or list. This means that instead of doing something like this:

  $input = "foo.bar.baz"
  $parts = $input.Split(".")
  $foo = $parts[0]
  $bar = $parts[1]
  $baz = $parts[2]
  

  You can simply do this:

  $foo, $bar, $baz = $input.Split(".")
  

  Since Powershell treats assignments in this manner like lists, if there are more values in the list than items in your list of variables to assign them to, the last variable becomes an array of the remaining values. This means you can also do things like this:

  $foo, $leftover = $input.Split(".") #Sets $foo = "foo", $leftover = ["bar","baz"]
  $bar = $leftover[0] # $bar = "bar"
  $baz = $leftover[1] # $baz = "baz"
  

  created Aug 25 '16 at 7:30

  
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• -1

  Reading a CmdLet Output
  -1

  By Default, powershell would return the output to the calling Entity. Consider Below Example,

  Get-Process -Name excel   
  

  This would simply, return the running process which matches the name excel, to the calling entity. In this case, the PowerShell Host. It prints something like,

  Handles  NPM(K)    PM(K)      WS(K) VM(M)   CPU(s)     Id  SI ProcessName                                                                                                                     
  -------  ------    -----      ----- -----   ------     --  -- -----------                                                                                                                     
     1037      54    67632      62544   617     5.23   4544   1 EXCEL 
  

  Now if you assign the output to a variable, it simply wont print anything. And of course the variable holds the output. (Be it a string, Object - Any type for that matter)

  $allExcel = Get-Process -Name excel
  

  So, lets say you have a scenario where you want to assign a variable by a Dynamic name, you can use the -OutVariable parameter

  Get-Process -Name excel -OutVariable AllRunningExcel
  

  Note that the '$' is missing here. A major difference between these two assignments is that, it also prints the output apart from assigning it to the variable AllRunningExcel. You can also choose to assign it to an another variable.

  $VarOne = Get-Process -Name excel -OutVariable VarTwo
  

  Albeit, the above scenario is very rare, both variables $VarOne & $VarTwo will have the same value.

  Now consider this,

  Get-Process -Name EXCEL -OutVariable MSOFFICE
  Get-Process -Name WINWORD -OutVariable +MSOFFICE
  

  The first statement would simply get excel process & assign it to MSOFFICE variable, and next would get ms word processes running and "Append" it to the existing value of MSOFFICE. It would look something like this,

  Handles  NPM(K)    PM(K)      WS(K) VM(M)   CPU(s)     Id  SI ProcessName                                                                                                                     
  -------  ------    -----      ----- -----   ------     --  -- -----------                                                                                                                     
     1047      54    67720      64448   618     5.70   4544   1 EXCEL                                                                                                                           
     1172      70    50052      81780   584     1.83  14968   1 WINWORD     
  

  edited Dec 16 '16 at 14:17

  

  

  
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