FileSystem/Install-Junction.ps1
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# Copyright 2012 Aaron Jensen # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. function Install-Junction { <# .SYNOPSIS Creates a junction, or updates an existing junction if its target is different. .DESCRIPTION Creates a junction given by `-Link` which points to the path given by `-Target`. If `Link` exists, deletes it and re-creates it if it doesn't point to `Target`. Both `-Link` and `-Target` parameters accept relative paths for values. Any non-rooted paths are converted to full paths using the current location, i.e. the path returned by `Get-Location`. .LINK New-Junction .LINK Remove-Junction .EXAMPLE Install-Junction -Link 'C:\Windows\system32Link' -Target 'C:\Windows\system32' Creates the `C:\Windows\system32Link` directory, which points to `C:\Windows\system32`. .EXAMPLE Install-Junction -Link C:\Projects\Foobar -Target 'C:\Foo\bar' -Force This example demonstrates how to create the target directory if it doesn't exist. After this example runs, the directory `C:\Foo\bar` and junction `C:\Projects\Foobar` will be created. #> [CmdletBinding(SupportsShouldProcess=$true)] param( [Parameter(Mandatory=$true)] [Alias("Junction")] [string] # The junction to create/update. Relative paths are converted to absolute paths using the current location. $Link, [Parameter(Mandatory=$true)] [string] # The target of the junction, i.e. where the junction will point to. Relative paths are converted to absolute paths using the curent location. $Target, [Switch] # Create the target directory if it does not exist. $Force ) Set-StrictMode -Version Latest $Link = Resolve-FullPath -Path $Link $Target = Resolve-FullPath -Path $Target if( Test-Path -Path $Target -PathType Leaf ) { Write-Error ('Unable to create junction {0}: target {1} exists and is a file.' -f $Link,$Target) return } if( -not (Test-Path -Path $Target -PathType Container) ) { if( $Force ) { $null = New-Item -Path $Target -ItemType Directory -Force } else { Write-Error ('Unable to create junction {0}: target {1} not found. Use the `-Force` switch to create target paths that don''t exist.' -f $Link,$Target) return } } if( Test-Path $Link -PathType Container ) { $junction = Get-Item $Link -Force if( -not $junction.IsJunction ) { Write-Error ('Failed to create junction ''{0}'': a directory exists with that path and it is not a junction.' -f $Link) return } if( $junction.TargetPath -eq $Target ) { return } Remove-Junction -Path $Link } if( $PSCmdlet.ShouldProcess( $Target, ("creating '{0}' junction" -f $Link) ) ) { $null = New-Junction -Link $Link -Target $target } } |