Adding a rule
The following simple example tries to demonstrate how a combination of get-acl and set-acl can be used to add an identity to the set of users that are allowed access to a directory:
#
# Create a dummy directory to test on it:
#
$null = new-item -itemType directory foo
#
# Get the directory's access control list
#
$acl = get-acl foo
#
# The following would show the access list
#
# $acl.Access
#
# Create a new rule to grant (allow) FullControl to NT SERVICE\MSSQLSERVER:
#
$ident = new-object System.Security.Principal.NTAccount 'NT SERVICE\MSSQLSERVER'
$rule = new-object System.Security.AccessControl.FileSystemAccessRule `
$ident , `
([type]'System.Security.AccessControl.FileSystemRights' )::FullControl, `
([type]'System.Security.AccessControl.AccessControlType')::Allow `
$acl.AddAccessRule($rule)
set-acl foo $acl
# remove-item foo