Join-String

Join-String
    [[-Property] <PSPropertyExpression>]
    [[-Separator] <String>]
    [-OutputPrefix <String>]
    [-OutputSuffix <String>]
    [-UseCulture]
    [-InputObject <PSObject[]>]
    [<CommonParameters>]

Join-String
    [[-Property] <PSPropertyExpression>]
    [[-Separator] <String>]
    [-OutputPrefix <String>]
    [-OutputSuffix <String>]
    [-SingleQuote]
    [-UseCulture]
    [-InputObject <PSObject[]>]
    [<CommonParameters>]

Join-String
    [[-Property] <PSPropertyExpression>]
    [[-Separator] <String>]
    [-OutputPrefix <String>]
    [-OutputSuffix <String>]
    [-DoubleQuote]
    [-UseCulture]
    [-InputObject <PSObject[]>]
    [<CommonParameters>]

Join-String
    [[-Property] <PSPropertyExpression>]
    [[-Separator] <String>]
    [-OutputPrefix <String>]
    [-OutputSuffix <String>]
    [-FormatString <String>]
    [-UseCulture]
    [-InputObject <PSObject[]>]
    [<CommonParameters>]

The Join-String cmdlet joins, or combines, text from pipeline objects into a single string.

If no parameters are specified, the pipeline objects are converted to a string and joined with the default separator $OFS.

By specifying a property name, the property's value is converted to a string and joined into a string.

Instead of a property name, a script block can be used. The script block's result is converted to a string before it's joined to form the result. It can either combine the text of an object's property or the result of the object that was converted to a string.

This cmdlet was introduced in PowerShell 6.2.

This example joins directory names, wraps the output in double-quotes, and separates the directory names with a comma and space (, ). The output is a string object.

Get-ChildItem -Directory C:\ | Join-String -Property Name -DoubleQuote -Separator ', '

"PerfLogs", "Program Files", "Program Files (x86)", "Users", "Windows"

Get-ChildItem uses the Directory parameter to get all the directory names for the C:\ drive. The objects are sent down the pipeline to Join-String. The Property parameter specifies the directory names. The DoubleQuote parameter wraps the directory names with double-quote marks. The Separator parameter specifies to use a comma and space (, ) to separate the directory names.

The Get-ChildItem objects are System.IO.DirectoryInfo and Join-String converts the objects to System.String.

This example uses a substring method to get the first four letters of directory names, wraps the output in single-quotes, and separates the directory names with a semicolon (;).

Get-ChildItem -Directory C:\ | Join-String -Property {$_.Name.SubString(0,4)} -SingleQuote -Separator ';'

'Perf';'Prog';'Prog';'User';'Wind'

Get-ChildItem uses the Directory parameter to get all the directory names for the C:\ drive. The objects are sent down the pipeline to Join-String.

The Property parameter script block uses automatic variable ($_) to specify each object's Name property substring. The substring gets the first four letters of each directory name. The substring specifies the character start and end positions. The SingleQuote parameter wraps the directory names with single-quote marks. The Separator parameter specifies to use a semicolon (;) to separate the directory names.

For more information about automatic variables and substrings, see about_Automatic_Variables and Substring.

This example joins service names with each service on a separate line and indented by a tab.

Get-Service -Name se* | Join-String -Property Name -Separator "`r`n`t" -OutputPrefix "Services:`n`t"

Services:
    seclogon
    SecurityHealthService
    SEMgrSvc
    SENS
    Sense
    SensorDataService
    SensorService
    SensrSvc
    SessionEnv

Get-Service uses the Name parameter with to specify services that begin with se*. The asterisk (*) is a wildcard for any character.

The objects are sent down the pipeline to Join-String that uses the Property parameter to specify the service names. The Separator parameter specifies three special characters that represent a carriage return (`r), newline (`n), and tab (`t). The OutputPrefix inserts a label Services: with a new line and tab before the first line of output.

For more information about special characters, see about_Special_Characters.

This example generates a PowerShell class definition using an existing object as a template.

This code sample uses splatting to reduce the line length and improve readability. For more information, see about_Splatting.

$obj = [pscustomobject] @{Name = "Joe"; Age = 42}
$parms = @{
  Property = "Name"
  FormatString = '  ${0}'
  OutputPrefix = "class {`n"
  OutputSuffix = "`n}`n"
  Separator = "`n"
}
$obj.psobject.Properties | Join-String @parms

class {
  $Name
  $Age
}

This cmdlet supports the common parameters: -Debug, -ErrorAction, -ErrorVariable, -InformationAction, -InformationVariable, -OutBuffer, -OutVariable, -PipelineVariable, -ProgressAction, -Verbose, -WarningAction, and -WarningVariable. For more information, see about_CommonParameters.