#
# Lets get the top 5 file types by size
#
# First we store all the files in variable so we don't have to keep fetching them.
$everything = dir c:\Windows\system32 -recurse -ea 0
#
# So Here is the Goal
#
$everything | ?{!$_.PSIsContainer} | Group-Object Extension | select name,@{n="GroupSizeMB";e={[int]((($_.group | measure-object -sum Length).sum)/1MB)}} | sort -desc GroupSizeMB | select -first 5
#
# That was very simple, but unless your familar with Powershell that line could be daunting. Lets break it down. 
#
# First, we need to get all the files in a directory
#
$everything | select -first 100
#
# Hmmm, it seems we have folders in there too. Need to get rid of those 
$everything | ?{!$_.PSIsContainer} | select -first 100
#
# Now that we have all the files. We need to group them by Extension
#
$everything | ?{!$_.PSIsContainer} | Group-Object Extension
#
# The next part is a little complicated, but really all it does is creates new properties base on other values
# Its what we call a Calculated Properties. Meaning they are built off other values.
#
$everything | ?{!$_.PSIsContainer} | Group-Object Extension | select name,@{n="GroupSizeMB";e={[int]((($_.group | measure-object -sum Length).sum)/1MB)}}
#
# Next we want to sort them Descending using the Property we created call GroupSizeMB
#
$everything | ?{!$_.PSIsContainer} | Group-Object Extension | select name,@{n="GroupSizeMB";e={[int]((($_.group | measure-object -sum Length).sum)/1MB)}} | sort -desc GroupSizeMB
#
# Finally we only want the top five so we can use select to only return five
#
$everything | ?{!$_.PSIsContainer} | Group-Object Extension | select name,@{n="GroupSizeMB";e={[int]((($_.group | measure-object -sum Length).sum)/1MB)}} | sort -desc GroupSizeMB | select -first 5
#
# It was curious that we had a large amount of space being used by files with no extensions. How do we figure that out
#
$everything | ?{!$_.PSIsContainer} | Group-Object Extension | ?{$_.Name -match "^$"}
#
# To see the actual files
#
$everything | ?{!$_.PSIsContainer} | Group-Object Extension | ?{$_.Name -match "^$"} | %{$_.Group} | Select FullName,Length