NAME
    Compare-Object

SYNOPSIS
    Compares two sets of objects.

SYNTAX
    Compare-Object [-ReferenceObject] <PSObject[]> [-DifferenceObject] <PSObject[]> [-CaseSensitive] [-Culture <string>] [-ExcludeDifferent] [-IncludeEqual] [-PassThru] [-Property <Object[]>] [-SyncWindow <int>] [<CommonParameters>]

DESCRIPTION
    The Compare-Object cmdlet compares two sets of objects. One set of objects is the Reference set, and the other set is the Difference set.

    The result of the comparison indicates whether a property value appeared only in the object from the Reference set (indicated by the <= symbol), only in the object from the Difference set (indicated by the => symbol) or, if the IncludeEqual parameter is specified, in both objects (indicated by the == symbol).

PARAMETERS
    -CaseSensitive [<SwitchParameter>]
        Indicates that comparisons should be case-sensitive.

        Required?                    false
        Position?                    named
        Default value
        Accept pipeline input?     false
        Accept wildcard characters? false

    -Culture <string>
        Specifies the culture to use for comparisons.

        Required?                    false
        Position?                    named
        Default value
        Accept pipeline input?     false
        Accept wildcard characters? false

    -DifferenceObject <PSObject[]>
        Specifies the objects that are compared to the reference objects.

        Required?                    true
        Position?                    2
        Default value
        Accept pipeline input?     true (ByValue)
        Accept wildcard characters? false

    -ExcludeDifferent [<SwitchParameter>]
        Displays only the characteristics of compared objects that are equal.

        Required?                    false
        Position?                    named
        Default value
        Accept pipeline input?     false
        Accept wildcard characters? false

    -IncludeEqual [<SwitchParameter>]
        Displays characteristics of compared objects that are equal. By default, only characteristics that differ between the reference and difference objects are displayed.

        Required?                    false
        Position?                    named
        Default value
        Accept pipeline input?     false
        Accept wildcard characters? false

    -PassThru [<SwitchParameter>]
        Passes the objects that differed to the pipeline. By default, this cmdlet does not generate any output.

        Required?                    false
        Position?                    named
        Default value
        Accept pipeline input?     false
        Accept wildcard characters? false

    -Property <Object[]>
        Specifies the properties of the reference and difference objects to compare.

        Required?                    false
        Position?                    named
        Default value
        Accept pipeline input?     false
        Accept wildcard characters? false

    -ReferenceObject <PSObject[]>
        Objects used as a reference for comparison.

        Required?                    true
        Position?                    1
        Default value
        Accept pipeline input?     false
        Accept wildcard characters? false

    -SyncWindow <int>
        Defines a search region in which an attempt is made to re-synchronize the order if there is no match. The default value is [Int32]::MaxValue.

        Required?                    false
        Position?                    named
        Default value                [Int32]::MaxValue
        Accept pipeline input?     false
        Accept wildcard characters? false

    <CommonParameters>
        This cmdlet supports the common parameters: Verbose, Debug,
        ErrorAction, ErrorVariable, WarningAction, WarningVariable,
        OutBuffer and OutVariable. For more information, type,
        “Get-Help about_CommonParameters“.

INPUTS
    System.Management.Automation.PSObject
        You can pipe a DifferenceObject object to Compare-Object.

OUTPUTS
    None, or the objects that are different
        When you use the PassThru parameter, Compare-Object returns the objects that differed. Otherwise, this cmdlet does not generate any output.

NOTES

    ————————– EXAMPLE 1 ————————–

    C:\PS>Compare-Object -ReferenceObject $(Get-Content C:\test\testfile1.txt) -DifferenceObject $(Get-Content C:\test\testfile2.txt)

    Description
    ———–
    This command compares the contents of two text files. It displays only the lines that appear in one file or in the other file, not lines that appear in both files.

    ————————– EXAMPLE 2 ————————–

    C:\PS>Compare-Object -ReferenceObject $(Get-Content C:\Test\testfile1.txt) -DifferenceObject $(Get-Content C:\Test\testfile2.txt) -IncludeEqual

    Description
    ———–
    This command compares each line of content in two text files. It displays all lines of content from both files, indicating whether each line appears in only Textfile1.txt or Textfile2.txt or whether each line appears in both files.

    ————————– EXAMPLE 3 ————————–

    C:\PS>$processes_before = Get-Process

    C:\PS> notepad

    C:\PS> $processes_after = Get-Process

    C:\PS> Compare-Object -ReferenceObject $processes_before -DifferenceObject $processes_after

    Description
    ———–
    These commands compare two sets of process objects.

    The first command uses the Get-Process cmdlet to get the processes on the computer. It stores them in the $processes_before Variable.

    The second command starts Notepad.

    The third command uses the Get-Process cmdlet again and stores the resulting processes in the $processes_after Variable.

    The fourth command uses the Compare-Object cmdlet to compare the two sets of process objects. It displaysthe differences between them, which include the new instance of Notepad.

RELATED LINKS
    Online version: http://go.microsoft.com/fwlink/?LinkID=113286
    Group-Object
    Measure-Object
    Sort-Object
    ForEach-Object
    New-Object
    Select-Object
    Tee-Object
    Where-Object