powershell3

Get-Alias group

group
group-object

PS F:docpic> ls|group Extension

PS F:docpic> ls|group {$_.Length -gt 50kb}
PS F:docpic> ls|group {$_.Name.Substring(0,1).ToUpper()}
PS F:docpic> Get-Process|group Company -NoElement
PS F:docpic> Get-Process|Get-Member|sort name