[file-permissions] PowerShell To Set Folder Permissions

I am trying to use the "default" options in applying folder permissions; by that, I mean that using the "Full Controll, Write, Read, etc" in the 'Properties' for a folder.

The following script works to add the user in, but it applies "Special Permissions" - not the ones with the tick boxes for the ones visible in the properties menu of the folder:

$Acl = Get-Acl "\\R9N2WRN\Share"

$Ar = New-Object System.Security.AccessControl.FileSystemAccessRule ("user","FullControl","Allow")

$Acl.SetAccessRule($Ar)
Set-Acl "\\R9N2WRN\Share" $Acl

What am I doing wrong please?

$path = "C:\DemoFolder"
$acl = Get-Acl $path
$username = [System.Security.Principal.WindowsIdentity]::GetCurrent().Name
$Attribs = $username, "FullControl", "ContainerInherit,ObjectInherit", "None", "Allow"
$AccessRule = New-Object System.Security.AcessControl.FileSystemAccessRule($Attribs)
$acl.SetAccessRule($AccessRule)
$acl | Set-Acl $path
Get-ChildItem -Path "$path" -Recourse -Force | Set-Acl -aclObject $acl -Verbose

Another example using PowerShell for set permissions (File / Directory) :

Verify permissions

Get-Acl "C:\file.txt" | fl *

Apply full permissions for everyone

$acl = Get-Acl "C:\file.txt"
$accessRule = New-Object System.Security.AccessControl.FileSystemAccessRule("everyone","FullControl","Allow")
$acl.SetAccessRule($accessRule)
$acl | Set-Acl "C:\file.txt"

Screenshots:

Hope this helps

In case you had to deal with a lot of subfolders contatining subfolders and other recursive stuff. Small improvment of @Mike L'Angelo:

$mypath = "path_to_folder"
$myacl = Get-Acl $mypath
$myaclentry = "username","FullControl","Allow"
$myaccessrule = New-Object System.Security.AccessControl.FileSystemAccessRule($myaclentry)
$myacl.SetAccessRule($myaccessrule)
Get-ChildItem -Path "$mypath" -Recurse -Force | Set-Acl -AclObject $myacl -Verbose

Verbosity is optional in the last line

Referring to Gamaliel 's answer: $args is an array of the arguments that are passed into a script at runtime - as such cannot be used the way Gamaliel is using it. This is actually working:

$myPath = 'C:\whatever.file'
# get actual Acl entry
$myAcl = Get-Acl "$myPath"
$myAclEntry = "Domain\User","FullControl","Allow"
$myAccessRule = New-Object System.Security.AccessControl.FileSystemAccessRule($myAclEntry)
# prepare new Acl
$myAcl.SetAccessRule($myAccessRule)
$myAcl | Set-Acl "$MyPath"
# check if added entry present
Get-Acl "$myPath" | fl