Remove item level permission for specific user using powershell

Question

I want to remove the permission for each item and then want to add my unique permission I have tried the code for giving permission. But firstly, i want to remove it and then add new permission. My code is as below:

    $clientlist.Items | ForEach-Object{
                $clientlist.BreakRoleInheritance($True)
                $userNew = $webNew.EnsureUser($user)
                $roleDefinition = $webNew.RoleDefinitions[$PermissionLevel]
                $roleAssignment = New-Object Microsoft.SharePoint.SPRoleAssignment($userNew)
                $roleAssignment.RoleDefinitionBindings.Add($roleDefinition)
                $clientlist.RoleAssignments.Add($roleAssignment)
                $clientlist.Update()
                Write-Host "Successfully added $PermissionLevel permission to $UserNew in $clientlist list. " -foregroundcolor Green

}

Thanks.

Answer 1

To remove permissions for a given user:

    $clientlist.RoleAssignments.RemoveById($userOld.ID)

This will remove all permissions for a given user. You can use the same method on folders or list items.

Answer 2

Change $clientlist.BreakRoleInheritance($True) to $clientlist.BreakRoleInheritance($false) as $true in the argument of BreakRoleInheritance specifies that permissions from the parent be copied over to child. If you don't want any permissions from parent to be passed over user $false