Get-FolderPathContainingScript.ps1

function Get-FolderPathContainingScript {
    # Returns the path to the folder containing the running script. If no script is
    # running, the function returns the current path
    #
    # Example:
    # Get-FolderPathContainingScript
    #
    # This example returns the folder that contains the currently running script. Or,
    # if no script is running, the function returns the current folder
    #
    # The function outputs a [string] object representing the path to the folder
    #
    # PowerShell v1 - v2 do not have a $PSScriptRoot variable, so this function uses
    # other methods to determine the script directory
    #
    # Version 1.0.20250106.0

    #region License ############################################################
    # Copyright (c) 2025 Frank Lesniak
    #
    # Permission is hereby granted, free of charge, to any person obtaining a copy
    # of this software and associated documentation files (the "Software"), to deal
    # in the Software without restriction, including without limitation the rights
    # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    # copies of the Software, and to permit persons to whom the Software is
    # furnished to do so, subject to the following conditions:
    #
    # The above copyright notice and this permission notice shall be included in
    # all copies or substantial portions of the Software.
    #
    # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    # SOFTWARE.
    #endregion License ############################################################

    #region DownloadLocationNotice #############################################
    # The most up-to-date version of this script can be found on the author's
    # GitHub repository at https://github.com/franklesniak/PowerShell_Resources
    #endregion DownloadLocationNotice #############################################

    function Get-PSVersion {
        # .SYNOPSIS
        # Returns the version of PowerShell that is running.
        #
        # .DESCRIPTION
        # The function outputs a [version] object representing the version of
        # PowerShell that is running.
        #
        # On versions of PowerShell greater than or equal to version 2.0, this
        # function returns the equivalent of $PSVersionTable.PSVersion
        #
        # PowerShell 1.0 does not have a $PSVersionTable variable, so this
        # function returns [version]('1.0') on PowerShell 1.0.
        #
        # .EXAMPLE
        # $versionPS = Get-PSVersion
        # # $versionPS now contains the version of PowerShell that is running.
        # # On versions of PowerShell greater than or equal to version 2.0,
        # # this function returns the equivalent of $PSVersionTable.PSVersion.
        #
        # .INPUTS
        # None. You can't pipe objects to Get-PSVersion.
        #
        # .OUTPUTS
        # System.Version. Get-PSVersion returns a [version] value indiciating
        # the version of PowerShell that is running.
        #
        # .NOTES
        # Version: 1.0.20250106.0

        #region License ####################################################
        # Copyright (c) 2025 Frank Lesniak
        #
        # Permission is hereby granted, free of charge, to any person obtaining
        # a copy of this software and associated documentation files (the
        # "Software"), to deal in the Software without restriction, including
        # without limitation the rights to use, copy, modify, merge, publish,
        # distribute, sublicense, and/or sell copies of the Software, and to
        # permit persons to whom the Software is furnished to do so, subject to
        # the following conditions:
        #
        # The above copyright notice and this permission notice shall be
        # included in all copies or substantial portions of the Software.
        #
        # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
        # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
        # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
        # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
        # BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
        # ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
        # CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
        # SOFTWARE.
        #endregion License ####################################################

        if (Test-Path variable:\PSVersionTable) {
            return ($PSVersionTable.PSVersion)
        } else {
            return ([version]('1.0'))
        }
    }

    $strFolderPathContainingScript = ''
    if (Test-Path variable:\PSScriptRoot) {
        # $PSScriptRoot exists
        if (-not [string]::IsNullOrEmpty($PSScriptRoot)) {
            $strFolderPathContainingScript = $PSScriptRoot
        }
    }

    if ([string]::IsNullOrEmpty($strFolderPathContainingScript)) {
        # $PSScriptRoot does not exist or is empty
        # Either PowerShell v1 or v2 is running, or there may not be a script running

        $strScriptPath = ''
        if (Test-Path variable:\HostInvocation) {
            # Edge case for Sapien PrimalScript/PowerShell Studio
            $strScriptPath = $HostInvocation.MyCommand.Path
        } elseif (Test-Path variable:script:MyInvocation) {
            $strScriptPath = (Get-Variable MyInvocation -Scope Script).Value.MyCommand.Definition
        }

        if (-not [string]::IsNullOrEmpty($strScriptPath)) {
            # $strScriptPath would be the path to a script file, if we are, in fact,
            # running inside a script.
            # Otherwise, $strScriptPath would be the last command that was run, in
            # which case Test-Path would fail.
            if (Test-Path $strScriptPath) {
                $strFolderPathContainingScript = (Split-Path $strScriptPath)
            }
        }

        if ([string]::IsNullOrEmpty($strFolderPathContainingScript)) {
            $strFolderPathContainingScript = (Get-Location).Path
            if ($Host.Name -eq 'ConsoleHost' -or $Host.Name -eq 'ServerRemoteHost' -or $Host.Name -eq 'Windows PowerShell ISE Host' -or $Host.Name -eq 'Visual Studio Code Host') {
                $versionPS = Get-PSVersion
                $strMessage = 'Get-FolderPathContainingScript: There does not appear to be a script running; the current directory <' + $strFolderPathContainingScript + '> will be used.'
                if ($versionPS.Major -ge 5) {
                    Write-Information $strMessage
                } else {
                    Write-Host $strMessage
                }
            } else {
                Write-Warning ('Get-FolderPathContainingScript: Powershell Host <' + $Host.Name + '> may not be compatible with this function, the current directory <' + $strFolderPathContainingScript + '> will be used.')
            }
        }
    }

    return $strFolderPathContainingScript
}