Sessions created using New-PSSession persist until the PSSession is removed (by Remove-PSSession) or the PowerShell session ends. The following example returns sessions created in the current PowerShell session:

PS> Get-PSSession | Select-Object Id, ComputerName, State

Id ComputerName State
-- ------------ -----
 1 PSTEST       Opened

If the ComputerName parameter is supplied, Get-PSSession will show sessions created on that computer. For example, imagine a session is created in one PowerShell console:

$session = New-PSSession -ComputerName PSTest -Name Example 

A second administrator console session will be able to view details of that session:

PS> Get-PSSession -ComputerName PSTest | Select-Object Name, ComputerName, State

Name     ComputerName  State
----     ------------  -----
Example  PSTest        Disconnected