Get-Content -Path E:\test11\data.txt | Sort-Object | Get-Unique
源文件：
AA0001 2014-06-30 15:27:13.073
AA0001 2014-06-30 15:27:13.073
AA0001 2014-06-30 15:27:13.073
AA0002 2014-06-30 15:27:30.607
AA0002 2014-06-30 15:28:00.467
AA0003 2014-06-30 15:28:20.297
AA0003 2014-06-30 15:28:20.297
过滤后：
AA0001 2014-06-30 15:27:13.073
AA0002 2014-06-30 15:27:30.607
AA0002 2014-06-30 15:28:00.467
AA0003 2014-06-30 15:28:20.297
过滤后，另存为新的文件，可以这样：
Get-Content -Path E:\test11\data.txt | Sort-Object | Get-Unique | Out-File -FilePath E:\test11\NewData.txt