Here are some Powershell possibilities to get the amount of sessions or Citrix’s Unique sessions.
Get all Citrix Sessions:
(Get-BrokerSession -MaxRecordCount 100000).count
Get the numbers of sessions per user:
Get-BrokerSession -MaxRecordCount 100000 | group-object UserName | Sort-Object -Descending count
You will get a list with Usernames (SamAccountName) and the Number of Sessions per User
Get the amount of logged in Users:
(Get-BrokerSession -MaxRecordCount 100000 | group-object UserName).count