PowerShell: Assign permission to read-only users on the list on all site levels.

	#
	# Description:
	# List-Level Permission settings and assign "Contribute" role definition to the visitors group.
	# To allow read-only users to post, update, delete comments.
	#
	# Created Date:
	# v1.0 - 07-12-2017
	#
	# Author:
	# Vikas Bansal
	#
	Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
	$listName = "TestList"
	#get all webs (sub-sites) under site collection
	$WebsColl = Get-SPSite https://sp2013.com | Get-SPWeb -Limit ALL
	#iterate through each sub-site change list permissions
	foreach($web in $WebsColl) {
	$commentsList = $web.Lists.TryGetList($listName)
	if($commentsList -ne $null)
	{
	Write-Host $listName " exists on the" $web.Title at URL $web.Url -ForegroundColor DarkBlue -BackgroundColor Yellow
	# Assign the "Contribute" RoleDefinition to the site's visitors group
	$visitorsSPGroup = $commentsList.ParentWeb.AssociatedVisitorGroup #$spWeb.Groups[$visitorsSPGroupName]
	if(!$commentsList.HasUniqueRoleAssignments) {
	$commentsList.BreakRoleInheritance($true)
	}
	$assignment = New-Object Microsoft.SharePoint.SPRoleAssignment($visitorsSPGroup)
	$assignment.RoleDefinitionBindings.Add(($commentsList.ParentWeb.RoleDefinitions | Where-Object { $_.Type -eq "Contributor" }))
	$commentsList.RoleAssignments.Add($assignment)
	$commentsList.Update()
	Write-Host $listName " permission is changed for readonly users on the" $web.Title at URL $web.Url -ForegroundColor DarkGreen -BackgroundColor White
	}
	else
	{
	Write-Host $listName " not exists on the" $web.Title at URL $web.Url -ForegroundColor Yellow -BackgroundColor Red
	}
	}

view raw PowerShell_AssignPermissionToReadOnlyUsersOnList.ps1 hosted with ❤ by GitHub