SharePoint: Powershell scripts for reading, deleting and adding Groups from a Site Collection

Here are couple of Powershell scripts to play around with the SharePoint groups and users.

Reading All the Users and Groups in a Site Collection

$site = Get-SPSite "SiteCollection URL" 
$groups = $site.RootWeb.sitegroups
foreach ($grp in $groups) {"Group: " + $grp.name; foreach ($user in $grp.users) {"" + $user.loginname + ""} }
$site.Dispose()

Adding Groups, Permission and Users to the respective groups to a Site Collection:

Function AddSnapIn()
{
 #handles exceptions caused by trying to add a snapin
 Trap [Exception]
 {
   continue; 
 }

 #Check that the required snapins are available , use a comma delimited list.
 #example
 # ("Microsoft.SharePoint.PowerShell", "Microsoft.Office.Excel")
 $RequiredSnapIns = ("Microsoft.SharePoint.PowerShell");
 ForEach ($SnapIn in $RequiredSnapIns)
 {
  if ( (Get-PSSnapin -Name $SnapIn -ErrorAction SilentlyContinue) -eq $null ) 
  { 
   Add-PsSnapin $SnapIn
  } 
  else 
  {
  }
 }
 [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint");
}
function AddPermissionLevel ($web, $groupName, $permLevel)
{
 $spGroup = $web.SiteGroups[$groupName]
 
    $assignment = New-Object Microsoft.SharePoint.SPRoleAssignment($spGroup)
    $role = $web.RoleDefinitions[$permLevel]
    $assignment.RoleDefinitionBindings.Add($role);
    $web.RoleAssignments.Add($assignment)
}


AddSnapIn;

#Get Site and Web objects
$site = Get-SPSite "URL to Site Collection"
$web = $site.RootWeb

#Get XML file containing groups and associated users
$groupsXML = [xml] (Get-Content ("GroupsandUsers.XML"))

 #Walk through each group node defined in the XML file
$groupsXML.Groups.Group | ForEach-Object {
 #Check to see if SharePoint group already exists in the site collection
 if ($web.SiteGroups[$_.name] -eq $null)
 {
   #If the SharePoint group doesn't exist already - create it from the name and description values at the node
   $newGroup = $web.SiteGroups.Add($_.name, $web.CurrentUser, $null, $_.description)
   AddPermissionLevel -web $web -groupName $_.name -permLevel $_.permLevel
   #Get SharePoint group from the site collection
   $group = $web.SiteGroups[$_.name]
                        #Uncomment following three lines if you want to add another groups as current group owner
   #$OwnerGroup = $web.SiteGroups["PMO_Owners"]
                        #$group.Owner = $OwnerGroup
   #$group.Update()
          #Add the users defined in the XML to the SharePoint group
   $_.Users.User | ForEach-Object {
   $group.Users.Add($_, "", "", "")
  }
 }
} 

#Dispose of Web and Site objects
$web.Dispose()
$site.Dispose()
Remove-PsSnapin Microsoft.SharePoint.PowerShell

The accompanying XML file i.e. "GroupsandUsers.XML" should look like this:

 
  
   Domain\Owners
  
 

Removing Groups from SiteCollection in Bulk

$spWeb = Get-SPWeb "SiteCollection URL"
$spGroups = $spWeb.SiteGroups
#Add groups in the following array as per your requirement
$groups = ("GroupName1", "GroupName2","GroupName3","GroupName4","GroupName5","GroupName6","GroupName7","GroupName8")
ForEach($group in $groups) {
   $spGroups.Remove($group)
} 
$spWeb.Dispose()

References:

• https://social.technet.microsoft.com/Forums/en-US/453ab8d3-f046-45bf-9571-4d01a995038a/how-to-create-user-groups-and-add-users-in-sharepoint-2010-site-collection-using-powershell?forum=sharepointadminprevious

• http://get-spscripts.com/2010/07/adding-groups-with-permission-levels-to.html