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How do I join two paths in powershell?

Published in PowerShell Path Management 3 mins read

In PowerShell, you join two or more path segments using the Join-Path cmdlet. This cmdlet is the recommended method for combining path strings, as it intelligently handles path separators and ensures the resulting path is correctly formatted for the operating system.

Understanding Join-Path

The [Join-Path](https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.management/join-path?view=powershell-7.4) cmdlet is designed to combine a path and a child path into a single, valid path. It automatically manages details like adding or removing backslashes (\) or forward slashes (/) to ensure the combined path is syntactically correct, making your scripts more robust and portable.

Join-Path Syntax and Parameters

The basic structure of Join-Path involves providing a base path and the child path you want to append. Here are its primary parameters:

  • -Path <String[]>: Specifies the initial path or paths to which the child path will be appended. This parameter can accept multiple path strings.
  • -ChildPath <String>: This is a mandatory parameter that specifies the directory or file name that will be appended to the -Path.
  • -AdditionalChildPath <String[]> (Optional): Allows you to specify one or more additional path segments to append after the -ChildPath. If multiple strings are provided, Join-Path will generate a combined path for each.
  • -Resolve (Optional): If present, Join-Path will attempt to resolve the combined path and return the actual items (e.g., files or directories) located at that path, instead of just the path string itself.
  • -Credential <PSCredential> (Optional): Provides a credential object for accessing paths that require specific authentication.

Practical Examples of Joining Paths

Here are various examples demonstrating how to use Join-Path effectively in different scenarios:

  • Basic Path Combination:

    Join-Path -Path "C:\Program Files" -ChildPath "Windows PowerShell"
    # Output: C:\Program Files\Windows PowerShell
  • Automatic Handling of Redundant Slashes (from Reference 3):
    Join-Path automatically corrects superfluous path separators.

    PS C:\> Join-Path -Path "path\\" -ChildPath "\\childpath"
    # Output: path\childpath
  • Joining Paths Without Slashes (from Reference 2):
    If the input path segments do not include slashes, Join-Path adds the correct separator.

    PS C:\> Join-Path -Path "path" -ChildPath "childpath"
    # Output: path\childpath
  • Appending an Additional Path Segment:
    You can build a longer path by adding an additional child path.

    Join-Path -Path "C:\Users" -ChildPath "Admin" -AdditionalChildPath "Documents"
    # Output: C:\Users\Admin\Documents
  • Generating Multiple Paths from a Single Base:
    By providing multiple values to -AdditionalChildPath, Join-Path will construct a complete path for each.

    Join-Path -Path "C:\Projects\MyProject" -ChildPath "Source" -AdditionalChildPath "App", "Tests"
    # Output:
    # C:\Projects\MyProject\Source\App
    # C:\Projects\MyProject\Source\Tests

Why Use Join-Path?

Utilizing Join-Path offers significant advantages over manually concatenating strings to form paths:

  • Platform Independence: It automatically uses the correct path separator for the operating system on which PowerShell is running, ensuring your scripts work correctly across Windows, Linux, and macOS.
  • Error Prevention: It intelligently handles scenarios where paths might have too many or too few slashes, preventing common path-related errors.
  • Readability and Maintainability: It makes your code clearer, more concise, and easier to maintain by abstracting away the complexities of path construction.

By incorporating Join-Path into your scripts, you can confidently build valid and robust paths, regardless of the input format or the execution environment.