[PowerShell每日技巧]根据文件夹前缀进行分组(20131206)

DAIC

Did you know that Group-Object can easily group elements by custom criteria? Here's a line that groups folders by their first three letters:

1. Get-ChildItem -Path C:\Windows -Directory |
   
2.    Group-Object -Property { $_.Name.PadRight(3).Substring(0,3)}

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And with little additional effort, you can create a hash table that uses these three letters as a key:

1. $lookup = Get-ChildItem -Path $env:windir -Directory  |
   
2.    Group-Object -Property { $_.Name.PadRight(3).Substring(0,3).ToUpper()} -AsHashTable -AsString
   
3. 
   
4. $lookup.Keys

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So now it is really trivial to get all folders that, let's say, start with "SYS":

PS>powershell -f test.ps1     Directory: C:\Windows Mode                LastWriteTime     Length Name ----                -------------     ------ ---- d----        11/27/2013   8:36 AM            System32 d----        11/27/2013   8:36 AM            SysWOW64

And why is that useful? Some companies use folder prefixes for business units. With this technique, it's easy to bundle all business unit folders together - you could then sum up their total storage space in a second step and create automatic reporting.

http://powershell.com/cs/blogs/tips/archive/2013/12/06/getting-folders-by-prefix.aspx