How to add an existing group to a newly created site through poweshell?

Question

I am creating sites through powershell and creating the groups for them. I have a situation where if the group is already existing group then I have to add that group to the site. Coz might be possible the site is not present and the group is present. For ex: the site name is "xyz" and the group name is "xyz_admin". Here if the group is already existing group while creating the site then I have to add it to the site.

I am adding the group like this:

Add-SPGroup.ps1 -url $url -Group ($webname+"_admins") -Role "Fuld kontrol" -Owner $global:loginName

but it gives me an error when the group is present.

Any help is appreciated in this aspect.

Thanks in advance.

Answer 1

if ($SPWeb.SiteGroups[$webname+"_admins"] -ne $null){
  Write-Host "Group "$GroupName" already exists!"
  $SPWeb.AssociatedGroups.Add($SPWeb.SiteGroups[$webname+"_admins"]);
  $desiredGroup = $SPWeb.SiteGroups[$webname+"_admins"]
  $roleAssignment = New-Object Microsoft.SharePoint.SPRoleAssignment($desiredGroup)
  $role = $SPWeb.RoleDefinitions["Contribute"]
  $roleAssignment.RoleDefinitionBindings.Add($role)
  $SPWeb.RoleAssignments.Add($roleAssignment)
  $SPWeb.Update()
  $SPWeb.Dispose()
  Break;
 } else
 {
  $owner = $SPWeb | Get-SPUser $OwnerName
  if ($MemberName -ne "") {  $member = $SPWeb | Get-SPUser $MemberName }
  $SPWeb.SiteGroups.Add($GroupName, $owner, $member, $Description)
  $SPGroup = $SPWeb.SiteGroups[$GroupName]
  $SPWeb.RoleAssignments.Add($SPGroup)
 }

Ref:
Powershell to create Sharepoint groups
Adding a security group to a SharePoint site via PowerShell